NAME | DESCRIPTION | NOTES | SEE ALSO | COLOPHON

PROC(5)                   Linux Programmer's Manual                  PROC(5)

NAME         top

       proc - process information pseudo-filesystem

DESCRIPTION         top

       The proc filesystem is a pseudo-filesystem which provides an
       interface to kernel data structures.  It is commonly mounted at
       /proc.  Most of it is read-only, but some files allow kernel
       variables to be changed.

       The following list describes many of the files and directories under
       the /proc hierarchy.

       /proc/[pid]
              There is a numerical subdirectory for each running process;
              the subdirectory is named by the process ID.  Each such
              subdirectory contains the following pseudo-files and
              directories.

       /proc/[pid]/auxv (since 2.6.0-test7)
              This contains the contents of the ELF interpreter information
              passed to the process at exec time.  The format is one
              unsigned long ID plus one unsigned long value for each entry.
              The last entry contains two zeros.

       /proc/[pid]/cgroup (since Linux 2.6.24)
              This file describes control groups to which the process/task
              belongs.  For each cgroup hierarchy there is one entry
              containing colon-separated fields of the form:

                  5:cpuacct,cpu,cpuset:/daemons

              The colon-separated fields are, from left to right:

                  1. hierarchy ID number

                  2. set of subsystems bound to the hierarchy

                  3. control group in the hierarchy to which the process
                     belongs

              This file is present only if the CONFIG_CGROUPS kernel
              configuration option is enabled.

       /proc/[pid]/clear_refs (since Linux 2.6.22)

              This is a write-only file, writable only by owner of the
              process.

              The following values may be written to the file:

              1 (since Linux 2.6.22)
                     Reset the PG_Referenced and ACCESSED/YOUNG bits for all
                     the pages associated with the process.  (Before kernel
                     2.6.32, writing any nonzero value to this file had this
                     effect.)

              2 (since Linux 2.6.32)
                     Reset the PG_Referenced and ACCESSED/YOUNG bits for all
                     anonymous pages associated with the process.

              3 (since Linux 2.6.32)
                     Reset the PG_Referenced and ACCESSED/YOUNG bits for all
                     file-mapped pages associated with the process.

              Clearing the PG_Referenced and ACCESSED/YOUNG bits provides a
              method to measure approximately how much memory a process is
              using.  One first inspects the values in the "Referenced"
              fields for the VMAs shown in /proc/[pid]/smaps to get an idea
              of the memory footprint of the process.  One then clears the
              PG_Referenced and ACCESSED/YOUNG bits and, after some measured
              time interval, once again inspects the values in the
              "Referenced" fields to get an idea of the change in memory
              footprint of the process during the measured interval.  If one
              is interested only in inspecting the selected mapping types,
              then the value 2 or 3 can be used instead of 1.

              A further value can be written to affect a different bit:

              4 (since Linux 3.11)
                     Clear the soft-dirty bit for all the pages associated
                     with the process.  This is used (in conjunction with
                     /proc/[pid]/pagemap) by the check-point restore system
                     to discover which pages of a process have been dirtied
                     since the file /proc/[pid]/clear_refs was written to.

              Writing any value to /proc/[pid]/clear_refs other than those
              listed above has no effect.

              The /proc/[pid]/clear_refs file is present only if the
              CONFIG_PROC_PAGE_MONITOR kernel configuration option is
              enabled.

       /proc/[pid]/cmdline
              This holds the complete command line for the process, unless
              the process is a zombie.  In the latter case, there is nothing
              in this file: that is, a read on this file will return 0
              characters.  The command-line arguments appear in this file as
              a set of strings separated by null bytes ('\0'), with a
              further null byte after the last string.

       /proc/[pid]/coredump_filter (since kernel 2.6.23)
              See core(5).

       /proc/[pid]/cpuset (since kernel 2.6.12)
              See cpuset(7).

       /proc/[pid]/cwd
              This is a symbolic link to the current working directory of
              the process.  To find out the current working directory of
              process 20, for instance, you can do this:

                  $ cd /proc/20/cwd; /bin/pwd

              Note that the pwd command is often a shell built-in, and might
              not work properly.  In bash(1), you may use pwd -P.

              In a multithreaded process, the contents of this symbolic link
              are not available if the main thread has already terminated
              (typically by calling pthread_exit(3)).

       /proc/[pid]/environ
              This file contains the environment for the process.  The
              entries are separated by null bytes ('\0'), and there may be a
              null byte at the end.  Thus, to print out the environment of
              process 1, you would do:

                  $ strings /proc/1/environ

       /proc/[pid]/exe
              Under Linux 2.2 and later, this file is a symbolic link
              containing the actual pathname of the executed command.  This
              symbolic link can be dereferenced normally; attempting to open
              it will open the executable.  You can even type
              /proc/[pid]/exe to run another copy of the same executable as
              is being run by process [pid].  In a multithreaded process,
              the contents of this symbolic link are not available if the
              main thread has already terminated (typically by calling
              pthread_exit(3)).

              Under Linux 2.0 and earlier, /proc/[pid]/exe is a pointer to
              the binary which was executed, and appears as a symbolic link.
              A readlink(2) call on this file under Linux 2.0 returns a
              string in the format:

                  [device]:inode

              For example, [0301]:1502 would be inode 1502 on device major
              03 (IDE, MFM, etc. drives) minor 01 (first partition on the
              first drive).

              find(1) with the -inum option can be used to locate the file.

       /proc/[pid]/fd/
              This is a subdirectory containing one entry for each file
              which the process has open, named by its file descriptor, and
              which is a symbolic link to the actual file.  Thus, 0 is
              standard input, 1 standard output, 2 standard error, and so
              on.

              For file descriptors for pipes and sockets, the entries will
              be symbolic links whose content is the file type with the
              inode.  A readlink(2) call on this file returns a string in
              the format:

                  type:[inode]

              For example, socket:[2248868] will be a socket and its inode
              is 2248868.  For sockets, that inode can be used to find more
              information in one of the files under /proc/net/.

              For file descriptors that have no corresponding inode (e.g.,
              file descriptors produced by epoll_create(2), eventfd(2),
              inotify_init(2), signalfd(2), and timerfd(2)), the entry will
              be a symbolic link with contents of the form

                  anon_inode:<file-type>

              In some cases, the file-type is surrounded by square brackets.

              For example, an epoll file descriptor will have a symbolic
              link whose content is the string anon_inode:[eventpoll].

              In a multithreaded process, the contents of this directory are
              not available if the main thread has already terminated
              (typically by calling pthread_exit(3)).

              Programs that will take a filename as a command-line argument,
              but will not take input from standard input if no argument is
              supplied, or that write to a file named as a command-line
              argument, but will not send their output to standard output if
              no argument is supplied, can nevertheless be made to use
              standard input or standard out using /proc/[pid]/fd.  For
              example, assuming that -i is the flag designating an input
              file and -o is the flag designating an output file:

                  $ foobar -i /proc/self/fd/0 -o /proc/self/fd/1 ...

              and you have a working filter.

              /proc/self/fd/N is approximately the same as /dev/fd/N in some
              UNIX and UNIX-like systems.  Most Linux MAKEDEV scripts
              symbolically link /dev/fd to /proc/self/fd, in fact.

              Most systems provide symbolic links /dev/stdin, /dev/stdout,
              and /dev/stderr, which respectively link to the files 0, 1,
              and 2 in /proc/self/fd.  Thus the example command above could
              be written as:

                  $ foobar -i /dev/stdin -o /dev/stdout ...

       /proc/[pid]/fdinfo/ (since kernel 2.6.22)
              This is a subdirectory containing one entry for each file
              which the process has open, named by its file descriptor.  The
              contents of each file can be read to obtain information about
              the corresponding file descriptor, for example:

                  $ cat /proc/12015/fdinfo/4
                  pos:    1000
                  flags:  01002002

              The pos field is a decimal number showing the current file
              offset.  The flags field is an octal number that displays the
              file access mode and file status flags (see open(2)).

              The files in this directory are readable only by the owner of
              the process.

       /proc/[pid]/io (since kernel 2.6.20)
              This file contains I/O statistics for the process, for
              example:

                  # cat /proc/3828/io
                  rchar: 323934931
                  wchar: 323929600
                  syscr: 632687
                  syscw: 632675
                  read_bytes: 0
                  write_bytes: 323932160
                  cancelled_write_bytes: 0

              The fields are as follows:

              rchar: characters read
                     The number of bytes which this task has caused to be
                     read from storage.  This is simply the sum of bytes
                     which this process passed to read(2) and similar system
                     calls.  It includes things such as terminal I/O and is
                     unaffected by whether or not actual physical disk I/O
                     was required (the read might have been satisfied from
                     pagecache).

              wchar: characters written
                     The number of bytes which this task has caused, or
                     shall cause to be written to disk.  Similar caveats
                     apply here as with rchar.

              syscr: read syscalls
                     Attempt to count the number of read I/O operations—that
                     is, system calls such as read(2) and pread(2).

              syscw: write syscalls
                     Attempt to count the number of write I/O operations—
                     that is, system calls such as write(2) and pwrite(2).

              read_bytes: bytes read
                     Attempt to count the number of bytes which this process
                     really did cause to be fetched from the storage layer.
                     This is accurate for block-backed filesystems.

              write_bytes: bytes written
                     Attempt to count the number of bytes which this process
                     caused to be sent to the storage layer.

              cancelled_write_bytes:
                     The big inaccuracy here is truncate.  If a process
                     writes 1MB to a file and then deletes the file, it will
                     in fact perform no writeout.  But it will have been
                     accounted as having caused 1MB of write.  In other
                     words: this field represents the number of bytes which
                     this process caused to not happen, by truncating
                     pagecache.  A task can cause "negative" I/O too.  If
                     this task truncates some dirty pagecache, some I/O
                     which another task has been accounted for (in its
                     write_bytes) will not be happening.

              Note: In the current implementation, things are a bit racy on
              32-bit systems: if process A reads process B's /proc/[pid]/io
              while process B is updating one of these 64-bit counters,
              process A could see an intermediate result.

       /proc/[pid]/limits (since kernel 2.6.24)
              This file displays the soft limit, hard limit, and units of
              measurement for each of the process's resource limits (see
              getrlimit(2)).  Up to and including Linux 2.6.35, this file is
              protected to allow reading only by the real UID of the
              process.  Since Linux 2.6.36, this file is readable by all
              users on the system.

       /proc/[pid]/map_files/ (since kernel 3.3)
              This subdirectory contains entries corresponding to memory-
              mapped files (see mmap(2)).  Entries are named by memory
              region start and end address pair (expressed as hexadecimal
              numbers), and are symbolic links to the mapped files
              themselves.  Here is an example, with the output wrapped and
              reformatted to fit on an 80-column display:

                  $ ls -l /proc/self/map_files/
                  lr--------. 1 root root 64 Apr 16 21:31
                              3252e00000-3252e20000 -> /usr/lib64/ld-2.15.so
                  ...

              Although these entries are present for memory regions that
              were mapped with the MAP_FILE flag, the way anonymous shared
              memory (regions created with the MAP_ANON | MAP_SHARED flags)
              is implemented in Linux means that such regions also appear on
              this directory.  Here is an example where the target file is
              the deleted /dev/zero one:

                  lrw-------. 1 root root 64 Apr 16 21:33
                              7fc075d2f000-7fc075e6f000 -> /dev/zero (deleted)

              This directory appears only if the CONFIG_CHECKPOINT_RESTORE
              kernel configuration option is enabled.

       /proc/[pid]/maps
              A file containing the currently mapped memory regions and
              their access permissions.  See mmap(2) for some further
              information about memory mappings.

              The format of the file is:

       address           perms offset  dev   inode       pathname
       00400000-00452000 r-xp 00000000 08:02 173521      /usr/bin/dbus-daemon
       00651000-00652000 r--p 00051000 08:02 173521      /usr/bin/dbus-daemon
       00652000-00655000 rw-p 00052000 08:02 173521      /usr/bin/dbus-daemon
       00e03000-00e24000 rw-p 00000000 00:00 0           [heap]
       00e24000-011f7000 rw-p 00000000 00:00 0           [heap]
       ...
       35b1800000-35b1820000 r-xp 00000000 08:02 135522  /usr/lib64/ld-2.15.so
       35b1a1f000-35b1a20000 r--p 0001f000 08:02 135522  /usr/lib64/ld-2.15.so
       35b1a20000-35b1a21000 rw-p 00020000 08:02 135522  /usr/lib64/ld-2.15.so
       35b1a21000-35b1a22000 rw-p 00000000 00:00 0
       35b1c00000-35b1dac000 r-xp 00000000 08:02 135870  /usr/lib64/libc-2.15.so
       35b1dac000-35b1fac000 ---p 001ac000 08:02 135870  /usr/lib64/libc-2.15.so
       35b1fac000-35b1fb0000 r--p 001ac000 08:02 135870  /usr/lib64/libc-2.15.so
       35b1fb0000-35b1fb2000 rw-p 001b0000 08:02 135870  /usr/lib64/libc-2.15.so
       ...
       f2c6ff8c000-7f2c7078c000 rw-p 00000000 00:00 0    [stack:986]
       ...
       7fffb2c0d000-7fffb2c2e000 rw-p 00000000 00:00 0   [stack]
       7fffb2d48000-7fffb2d49000 r-xp 00000000 00:00 0   [vdso]

              The address field is the address space in the process that the
              mapping occupies.  The perms field is a set of permissions:

                   r = read
                   w = write
                   x = execute
                   s = shared
                   p = private (copy on write)

              The offset field is the offset into the file/whatever; dev is
              the device (major:minor); inode is the inode on that device.
              0 indicates that no inode is associated with the memory
              region, as would be the case with BSS (uninitialized data).

              The pathname field will usually be the file that is backing
              the mapping.  For ELF files, you can easily coordinate with
              the offset field by looking at the Offset field in the ELF
              program headers (readelf -l).

              There are additional helpful pseudo-paths:

                   [stack]
                          The initial process's (also known as the main
                          thread's) stack.

                   [stack:<tid>] (since Linux 3.4)
                          A thread's stack (where the <tid> is a thread ID).
                          It corresponds to the /proc/[pid]/task/[tid]/
                          path.

                   [vdso] The virtual dynamically linked shared object.

                   [heap] The process's heap.

              If the pathname field is blank, this is an anonymous mapping
              as obtained via the mmap(2) function.  There is no easy way to
              coordinate this back to a process's source, short of running
              it through gdb(1), strace(1), or similar.

              Under Linux 2.0, there is no field giving pathname.

       /proc/[pid]/mem
              This file can be used to access the pages of a process's
              memory through open(2), read(2), and lseek(2).

       /proc/[pid]/mountinfo (since Linux 2.6.26)
              This file contains information about mount points.  It
              contains lines of the form:

              36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
              (1)(2)(3)   (4)   (5)      (6)      (7)   (8) (9)   (10)         (11)

              The numbers in parentheses are labels for the descriptions
              below:

              (1)  mount ID: unique identifier of the mount (may be reused
                   after umount(2)).

              (2)  parent ID: ID of parent mount (or of self for the top of
                   the mount tree).

              (3)  major:minor: value of st_dev for files on filesystem (see
                   stat(2)).

              (4)  root: root of the mount within the filesystem.

              (5)  mount point: mount point relative to the process's root.

              (6)  mount options: per-mount options.

              (7)  optional fields: zero or more fields of the form
                   "tag[:value]".

              (8)  separator: marks the end of the optional fields.

              (9)  filesystem type: name of filesystem in the form
                   "type[.subtype]".

              (10) mount source: filesystem-specific information or "none".

              (11) super options: per-superblock options.

              Parsers should ignore all unrecognized optional fields.
              Currently the possible optional fields are:

                   shared:X          mount is shared in peer group X

                   master:X          mount is slave to peer group X

                   propagate_from:X  mount is slave and receives propagation
                                     from peer group X (*)

                   unbindable        mount is unbindable

              (*) X is the closest dominant peer group under the process's
              root.  If X is the immediate master of the mount, or if there
              is no dominant peer group under the same root, then only the
              "master:X" field is present and not the "propagate_from:X"
              field.

              For more information on mount propagation see:
              Documentation/filesystems/sharedsubtree.txt in the Linux
              kernel source tree.

       /proc/[pid]/mounts (since Linux 2.4.19)
              This is a list of all the filesystems currently mounted in the
              process's mount namespace.  The format of this file is
              documented in fstab(5).  Since kernel version 2.6.15, this
              file is pollable: after opening the file for reading, a change
              in this file (i.e., a filesystem mount or unmount) causes
              select(2) to mark the file descriptor as readable, and poll(2)
              and epoll_wait(2) mark the file as having an error condition.

       /proc/[pid]/mountstats (since Linux 2.6.17)
              This file exports information (statistics, configuration
              information) about the mount points in the process's name
              space.  Lines in this file have the form:

              device /dev/sda7 mounted on /home with fstype ext3 [statistics]
              (       1      )            ( 2 )             (3 ) (4)

              The fields in each line are:

              (1)  The name of the mounted device (or "nodevice" if there is
                   no corresponding device).

              (2)  The mount point within the filesystem tree.

              (3)  The filesystem type.

              (4)  Optional statistics and configuration information.
                   Currently (as at Linux 2.6.26), only NFS filesystems
                   export information via this field.

              This file is readable only by the owner of the process.

       /proc/[pid]/ns/ (since Linux 3.0)
              This is a subdirectory containing one entry for each namespace
              that supports being manipulated by setns(2).  For information
              about namespaces, see clone(2).

       /proc/[pid]/ns/ipc (since Linux 3.0)
              Bind mounting this file (see mount(2)) to somewhere else in
              the filesystem keeps the IPC namespace of the process
              specified by pid alive even if all processes currently in the
              namespace terminate.

              Opening this file returns a file handle for the IPC namespace
              of the process specified by pid.  As long as this file
              descriptor remains open, the IPC namespace will remain alive,
              even if all processes in the namespace terminate.  The file
              descriptor can be passed to setns(2).

       /proc/[pid]/ns/net (since Linux 3.0)
              Bind mounting this file (see mount(2)) to somewhere else in
              the filesystem keeps the network namespace of the process
              specified by pid alive even if all processes in the namespace
              terminate.

              Opening this file returns a file handle for the network
              namespace of the process specified by pid.  As long as this
              file descriptor remains open, the network namespace will
              remain alive, even if all processes in the namespace
              terminate.  The file descriptor can be passed to setns(2).

       /proc/[pid]/ns/uts (since Linux 3.0)
              Bind mounting this file (see mount(2)) to somewhere else in
              the filesystem keeps the UTS namespace of the process
              specified by pid alive even if all processes currently in the
              namespace terminate.

              Opening this file returns a file handle for the UTS namespace
              of the process specified by pid.  As long as this file
              descriptor remains open, the UTS namespace will remain alive,
              even if all processes in the namespace terminate.  The file
              descriptor can be passed to setns(2).

       /proc/[pid]/numa_maps (since Linux 2.6.14)
              See numa(7).

       /proc/[pid]/oom_adj (since Linux 2.6.11)
              This file can be used to adjust the score used to select which
              process should be killed in an out-of-memory (OOM) situation.
              The kernel uses this value for a bit-shift operation of the
              process's oom_score value: valid values are in the range -16
              to +15, plus the special value -17, which disables OOM-killing
              altogether for this process.  A positive score increases the
              likelihood of this process being killed by the OOM-killer; a
              negative score decreases the likelihood.

              The default value for this file is 0; a new process inherits
              its parent's oom_adj setting.  A process must be privileged
              (CAP_SYS_RESOURCE) to update this file.

              Since Linux 2.6.36, use of this file is deprecated in favor of
              /proc/[pid]/oom_score_adj.

       /proc/[pid]/oom_score (since Linux 2.6.11)
              This file displays the current score that the kernel gives to
              this process for the purpose of selecting a process for the
              OOM-killer.  A higher score means that the process is more
              likely to be selected by the OOM-killer.  The basis for this
              score is the amount of memory used by the process, with
              increases (+) or decreases (-) for factors including:

              * whether the process creates a lot of children using fork(2)
                (+);

              * whether the process has been running a long time, or has
                used a lot of CPU time (-);

              * whether the process has a low nice value (i.e., > 0) (+);

              * whether the process is privileged (-); and

              * whether the process is making direct hardware access (-).

              The oom_score also reflects the adjustment specified by the
              oom_score_adj or oom_adj setting for the process.

       /proc/[pid]/oom_score_adj (since Linux 2.6.36)
              This file can be used to adjust the badness heuristic used to
              select which process gets killed in out-of-memory conditions.

              The badness heuristic assigns a value to each candidate task
              ranging from 0 (never kill) to 1000 (always kill) to determine
              which process is targeted.  The units are roughly a proportion
              along that range of allowed memory the process may allocate
              from, based on an estimation of its current memory and swap
              use.  For example, if a task is using all allowed memory, its
              badness score will be 1000.  If it is using half of its
              allowed memory, its score will be 500.

              There is an additional factor included in the badness score:
              root processes are given 3% extra memory over other tasks.

              The amount of "allowed" memory depends on the context in which
              the OOM-killer was called.  If it is due to the memory
              assigned to the allocating task's cpuset being exhausted, the
              allowed memory represents the set of mems assigned to that
              cpuset (see cpuset(7)).  If it is due to a mempolicy's node(s)
              being exhausted, the allowed memory represents the set of
              mempolicy nodes.  If it is due to a memory limit (or swap
              limit) being reached, the allowed memory is that configured
              limit.  Finally, if it is due to the entire system being out
              of memory, the allowed memory represents all allocatable
              resources.

              The value of oom_score_adj is added to the badness score
              before it is used to determine which task to kill.  Acceptable
              values range from -1000 (OOM_SCORE_ADJ_MIN) to +1000
              (OOM_SCORE_ADJ_MAX).  This allows user space to control the
              preference for OOM-killing, ranging from always preferring a
              certain task or completely disabling it from OOM-killing.  The
              lowest possible value, -1000, is equivalent to disabling OOM-
              killing entirely for that task, since it will always report a
              badness score of 0.

              Consequently, it is very simple for user space to define the
              amount of memory to consider for each task.  Setting a
              oom_score_adj value of +500, for example, is roughly
              equivalent to allowing the remainder of tasks sharing the same
              system, cpuset, mempolicy, or memory controller resources to
              use at least 50% more memory.  A value of -500, on the other
              hand, would be roughly equivalent to discounting 50% of the
              task's allowed memory from being considered as scoring against
              the task.

              For backward compatibility with previous kernels,
              /proc/[pid]/oom_adj can still be used to tune the badness
              score.  Its value is scaled linearly with oom_score_adj.

              Writing to /proc/[pid]/oom_score_adj or /proc/[pid]/oom_adj
              will change the other with its scaled value.

       /proc/[pid]/root
              UNIX and Linux support the idea of a per-process root of the
              filesystem, set by the chroot(2) system call.  This file is a
              symbolic link that points to the process's root directory, and
              behaves in the same way as exe, and fd/*.

              In a multithreaded process, the contents of this symbolic link
              are not available if the main thread has already terminated
              (typically by calling pthread_exit(3)).

       /proc/[pid]/smaps (since Linux 2.6.14)
              This file shows memory consumption for each of the process's
              mappings.  For each mapping there is a series of lines such as
              the following:

                  00400000-0048a000 r-xp 00000000 fd:03 960637       /bin/bash
                  Size:                552 kB
                  Rss:                 460 kB
                  Pss:                 100 kB
                  Shared_Clean:        452 kB
                  Shared_Dirty:          0 kB
                  Private_Clean:         8 kB
                  Private_Dirty:         0 kB
                  Referenced:          460 kB
                  Anonymous:             0 kB
                  AnonHugePages:         0 kB
                  Swap:                  0 kB
                  KernelPageSize:        4 kB
                  MMUPageSize:           4 kB
                  Locked:                0 kB

              The first of these lines shows the same information as is
              displayed for the mapping in /proc/[pid]/maps.  The remaining
              lines show the size of the mapping, the amount of the mapping
              that is currently resident in RAM ("Rss"), the process'
              proportional share of this mapping ("Pss"), the number of
              clean and dirty shared pages in the mapping, and the number of
              clean and dirty private pages in the mapping.  "Referenced"
              indicates the amount of memory currently marked as referenced
              or accessed.  "Anonymous" shows the amount of memory that does
              not belong to any file.  "Swap" shows how much would-be-
              anonymous memory is also used, but out on swap.

              The "KernelPageSize" entry is the page size used by the kernel
              to back a VMA.  This matches the size used by the MMU in the
              majority of cases.  However, one counter-example occurs on
              PPC64 kernels whereby a kernel using 64K as a base page size
              may still use 4K pages for the MMU on older processors.  To
              distinguish, this patch reports "MMUPageSize" as the page size
              used by the MMU.

              The "Locked" indicates whether the mapping is locked in memory
              or not.

              "VmFlags" field represents the kernel flags associated with
              the particular virtual memory area in two letter encoded
              manner.  The codes are the following:

                  rd  - readable
                  wr  - writable
                  ex  - executable
                  sh  - shared
                  mr  - may read
                  mw  - may write
                  me  - may execute
                  ms  - may share
                  gd  - stack segment grows down
                  pf  - pure PFN range
                  dw  - disabled write to the mapped file
                  lo  - pages are locked in memory
                  io  - memory mapped I/O area
                  sr  - sequential read advise provided
                  rr  - random read advise provided
                  dc  - do not copy area on fork
                  de  - do not expand area on remapping
                  ac  - area is accountable
                  nr  - swap space is not reserved for the area
                  ht  - area uses huge tlb pages
                  nl  - non-linear mapping
                  ar  - architecture specific flag
                  dd  - do not include area into core dump
                  sd  - soft-dirty flag
                  mm  - mixed map area
                  hg  - huge page advise flag
                  nh  - no-huge page advise flag
                  mg  - mergeable advise flag

              The /proc/[pid]/smaps file is present only if the
              CONFIG_PROC_PAGE_MONITOR kernel configuration option is
              enabled.

       /proc/[pid]/stack (since Linux 2.6.29)
              This file provides a symbolic trace of the function calls in
              this process's kernel stack.  This file is provided only if
              the kernel was built with the CONFIG_STACKTRACE configuration
              option.

       /proc/[pid]/stat
              Status information about the process.  This is used by ps(1).
              It is defined in /usr/src/linux/fs/proc/array.c.

              The fields, in order, with their proper scanf(3) format
              specifiers, are:

              pid %d      (1) The process ID.

              comm %s     (2) The filename of the executable, in
                          parentheses.  This is visible whether or not the
                          executable is swapped out.

              state %c    (3) One character from the string "RSDZTW" where R
                          is running, S is sleeping in an interruptible
                          wait, D is waiting in uninterruptible disk sleep,
                          Z is zombie, T is traced or stopped (on a signal),
                          and W is paging.

              ppid %d     (4) The PID of the parent.

              pgrp %d     (5) The process group ID of the process.

              session %d  (6) The session ID of the process.

              tty_nr %d   (7) The controlling terminal of the process.  (The
                          minor device number is contained in the
                          combination of bits 31 to 20 and 7 to 0; the major
                          device number is in bits 15 to 8.)

              tpgid %d    (8) The ID of the foreground process group of the
                          controlling terminal of the process.

              flags %u (%lu before Linux 2.6.22)
                          (9) The kernel flags word of the process.  For bit
                          meanings, see the PF_* defines in the Linux kernel
                          source file include/linux/sched.h.  Details depend
                          on the kernel version.

              minflt %lu  (10) The number of minor faults the process has
                          made which have not required loading a memory page
                          from disk.

              cminflt %lu (11) The number of minor faults that the process's
                          waited-for children have made.

              majflt %lu  (12) The number of major faults the process has
                          made which have required loading a memory page
                          from disk.

              cmajflt %lu (13) The number of major faults that the process's
                          waited-for children have made.

              utime %lu   (14) Amount of time that this process has been
                          scheduled in user mode, measured in clock ticks
                          (divide by sysconf(_SC_CLK_TCK)).  This includes
                          guest time, guest_time (time spent running a
                          virtual CPU, see below), so that applications that
                          are not aware of the guest time field do not lose
                          that time from their calculations.

              stime %lu   (15) Amount of time that this process has been
                          scheduled in kernel mode, measured in clock ticks
                          (divide by sysconf(_SC_CLK_TCK)).

              cutime %ld  (16) Amount of time that this process's waited-for
                          children have been scheduled in user mode,
                          measured in clock ticks (divide by
                          sysconf(_SC_CLK_TCK)).  (See also times(2).)  This
                          includes guest time, cguest_time (time spent
                          running a virtual CPU, see below).

              cstime %ld  (17) Amount of time that this process's waited-for
                          children have been scheduled in kernel mode,
                          measured in clock ticks (divide by
                          sysconf(_SC_CLK_TCK)).

              priority %ld
                          (18) (Explanation for Linux 2.6) For processes
                          running a real-time scheduling policy (policy
                          below; see sched_setscheduler(2)), this is the
                          negated scheduling priority, minus one; that is, a
                          number in the range -2 to -100, corresponding to
                          real-time priorities 1 to 99.  For processes
                          running under a non-real-time scheduling policy,
                          this is the raw nice value (setpriority(2)) as
                          represented in the kernel.  The kernel stores nice
                          values as numbers in the range 0 (high) to 39
                          (low), corresponding to the user-visible nice
                          range of -20 to 19.

                          Before Linux 2.6, this was a scaled value based on
                          the scheduler weighting given to this process.

              nice %ld    (19) The nice value (see setpriority(2)), a value
                          in the range 19 (low priority) to -20 (high
                          priority).

              num_threads %ld
                          (20) Number of threads in this process (since
                          Linux 2.6).  Before kernel 2.6, this field was
                          hard coded to 0 as a placeholder for an earlier
                          removed field.

              itrealvalue %ld
                          (21) The time in jiffies before the next SIGALRM
                          is sent to the process due to an interval timer.
                          Since kernel 2.6.17, this field is no longer
                          maintained, and is hard coded as 0.

              starttime %llu (was %lu before Linux 2.6)
                          (22) The time the process started after system
                          boot.  In kernels before Linux 2.6, this value was
                          expressed in jiffies.  Since Linux 2.6, the value
                          is expressed in clock ticks (divide by
                          sysconf(_SC_CLK_TCK)).

              vsize %lu   (23) Virtual memory size in bytes.

              rss %ld     (24) Resident Set Size: number of pages the
                          process has in real memory.  This is just the
                          pages which count toward text, data, or stack
                          space.  This does not include pages which have not
                          been demand-loaded in, or which are swapped out.

              rsslim %lu  (25) Current soft limit in bytes on the rss of the
                          process; see the description of RLIMIT_RSS in
                          getrlimit(2).

              startcode %lu
                          (26) The address above which program text can run.

              endcode %lu (27) The address below which program text can run.

              startstack %lu
                          (28) The address of the start (i.e., bottom) of
                          the stack.

              kstkesp %lu (29) The current value of ESP (stack pointer), as
                          found in the kernel stack page for the process.

              kstkeip %lu (30) The current EIP (instruction pointer).

              signal %lu  (31) The bitmap of pending signals, displayed as a
                          decimal number.  Obsolete, because it does not
                          provide information on real-time signals; use
                          /proc/[pid]/status instead.

              blocked %lu (32) The bitmap of blocked signals, displayed as a
                          decimal number.  Obsolete, because it does not
                          provide information on real-time signals; use
                          /proc/[pid]/status instead.

              sigignore %lu
                          (33) The bitmap of ignored signals, displayed as a
                          decimal number.  Obsolete, because it does not
                          provide information on real-time signals; use
                          /proc/[pid]/status instead.

              sigcatch %lu
                          (34) The bitmap of caught signals, displayed as a
                          decimal number.  Obsolete, because it does not
                          provide information on real-time signals; use
                          /proc/[pid]/status instead.

              wchan %lu   (35) This is the "channel" in which the process is
                          waiting.  It is the address of a location in the
                          kernel where the process is sleeping.  The
                          corresponding symbolic name can be found in
                          /proc/[pid]/wchan.

              nswap %lu   (36) Number of pages swapped (not maintained).

              cnswap %lu  (37) Cumulative nswap for child processes (not
                          maintained).

              exit_signal %d (since Linux 2.1.22)
                          (38) Signal to be sent to parent when we die.

              processor %d (since Linux 2.2.8)
                          (39) CPU number last executed on.

              rt_priority %u (since Linux 2.5.19; was %lu before Linux
              2.6.22)
                          (40) Real-time scheduling priority, a number in
                          the range 1 to 99 for processes scheduled under a
                          real-time policy, or 0, for non-real-time
                          processes (see sched_setscheduler(2)).

              policy %u (since Linux 2.5.19; was %lu before Linux 2.6.22)
                          (41) Scheduling policy (see
                          sched_setscheduler(2)).  Decode using the SCHED_*
                          constants in linux/sched.h.

              delayacct_blkio_ticks %llu (since Linux 2.6.18)
                          (42) Aggregated block I/O delays, measured in
                          clock ticks (centiseconds).

              guest_time %lu (since Linux 2.6.24)
                          (43) Guest time of the process (time spent running
                          a virtual CPU for a guest operating system),
                          measured in clock ticks (divide by
                          sysconf(_SC_CLK_TCK)).

              cguest_time %ld (since Linux 2.6.24)
                          (44) Guest time of the process's children,
                          measured in clock ticks (divide by
                          sysconf(_SC_CLK_TCK)).

       /proc/[pid]/statm
              Provides information about memory usage, measured in pages.
              The columns are:

                  size       (1) total program size
                             (same as VmSize in /proc/[pid]/status)
                  resident   (2) resident set size
                             (same as VmRSS in /proc/[pid]/status)
                  share      (3) shared pages (i.e., backed by a file)
                  text       (4) text (code)
                  lib        (5) library (unused in Linux 2.6)
                  data       (6) data + stack
                  dt         (7) dirty pages (unused in Linux 2.6)

       /proc/[pid]/status
              Provides much of the information in /proc/[pid]/stat and
              /proc/[pid]/statm in a format that's easier for humans to
              parse.  Here's an example:

                  $ cat /proc/$$/status
                  Name:   bash
                  State:  S (sleeping)
                  Tgid:   3515
                  Pid:    3515
                  PPid:   3452
                  TracerPid:      0
                  Uid:    1000    1000    1000    1000
                  Gid:    100     100     100     100
                  FDSize: 256
                  Groups: 16 33 100
                  VmPeak:     9136 kB
                  VmSize:     7896 kB
                  VmLck:         0 kB
                  VmHWM:      7572 kB
                  VmRSS:      6316 kB
                  VmData:     5224 kB
                  VmStk:        88 kB
                  VmExe:       572 kB
                  VmLib:      1708 kB
                  VmPTE:        20 kB
                  Threads:        1
                  SigQ:   0/3067
                  SigPnd: 0000000000000000
                  ShdPnd: 0000000000000000
                  SigBlk: 0000000000010000
                  SigIgn: 0000000000384004
                  SigCgt: 000000004b813efb
                  CapInh: 0000000000000000
                  CapPrm: 0000000000000000
                  CapEff: 0000000000000000
                  CapBnd: ffffffffffffffff
                  Cpus_allowed:   00000001
                  Cpus_allowed_list:      0
                  Mems_allowed:   1
                  Mems_allowed_list:      0
                  voluntary_ctxt_switches:        150
                  nonvoluntary_ctxt_switches:     545

              The fields are as follows:

              * Name: Command run by this process.

              * State: Current state of the process.  One of "R (running)",
                "S (sleeping)", "D (disk sleep)", "T (stopped)", "T (tracing
                stop)", "Z (zombie)", or "X (dead)".

              * Tgid: Thread group ID (i.e., Process ID).

              * Pid: Thread ID (see gettid(2)).

              * PPid: PID of parent process.

              * TracerPid: PID of process tracing this process (0 if not
                being traced).

              * Uid, Gid: Real, effective, saved set, and filesystem UIDs
                (GIDs).

              * FDSize: Number of file descriptor slots currently allocated.

              * Groups: Supplementary group list.

              * VmPeak: Peak virtual memory size.

              * VmSize: Virtual memory size.

              * VmLck: Locked memory size (see mlock(3)).

              * VmHWM: Peak resident set size ("high water mark").

              * VmRSS: Resident set size.

              * VmData, VmStk, VmExe: Size of data, stack, and text
                segments.

              * VmLib: Shared library code size.

              * VmPTE: Page table entries size (since Linux 2.6.10).

              * Threads: Number of threads in process containing this
                thread.

              * SigQ: This field contains two slash-separated numbers that
                relate to queued signals for the real user ID of this
                process.  The first of these is the number of currently
                queued signals for this real user ID, and the second is the
                resource limit on the number of queued signals for this
                process (see the description of RLIMIT_SIGPENDING in
                getrlimit(2)).

              * SigPnd, ShdPnd: Number of signals pending for thread and for
                process as a whole (see pthreads(7) and signal(7)).

              * SigBlk, SigIgn, SigCgt: Masks indicating signals being
                blocked, ignored, and caught (see signal(7)).

              * CapInh, CapPrm, CapEff: Masks of capabilities enabled in
                inheritable, permitted, and effective sets (see
                capabilities(7)).

              * CapBnd: Capability Bounding set (since kernel 2.6.26, see
                capabilities(7)).

              * Cpus_allowed: Mask of CPUs on which this process may run
                (since Linux 2.6.24, see cpuset(7)).

              * Cpus_allowed_list: Same as previous, but in "list format"
                (since Linux 2.6.26, see cpuset(7)).

              * Mems_allowed: Mask of memory nodes allowed to this process
                (since Linux 2.6.24, see cpuset(7)).

              * Mems_allowed_list: Same as previous, but in "list format"
                (since Linux 2.6.26, see cpuset(7)).

              * voluntary_context_switches, nonvoluntary_context_switches:
                Number of voluntary and involuntary context switches (since
                Linux 2.6.23).

       /proc/[pid]/task (since Linux 2.6.0-test6)
              This is a directory that contains one subdirectory for each
              thread in the process.  The name of each subdirectory is the
              numerical thread ID ([tid]) of the thread (see gettid(2)).
              Within each of these subdirectories, there is a set of files
              with the same names and contents as under the /proc/[pid]
              directories.  For attributes that are shared by all threads,
              the contents for each of the files under the task/[tid]
              subdirectories will be the same as in the corresponding file
              in the parent /proc/[pid] directory (e.g., in a multithreaded
              process, all of the task/[tid]/cwd files will have the same
              value as the /proc/[pid]/cwd file in the parent directory,
              since all of the threads in a process share a working
              directory).  For attributes that are distinct for each thread,
              the corresponding files under task/[tid] may have different
              values (e.g., various fields in each of the task/[tid]/status
              files may be different for each thread).

              In a multithreaded process, the contents of the
              /proc/[pid]/task directory are not available if the main
              thread has already terminated (typically by calling
              pthread_exit(3)).

       /proc/[pid]/wchan (since Linux 2.6.0)
              The symbolic name corresponding to the location in the kernel
              where the process is sleeping.

       /proc/apm
              Advanced power management version and battery information when
              CONFIG_APM is defined at kernel compilation time.

       /proc/bus
              Contains subdirectories for installed busses.

       /proc/bus/pccard
              Subdirectory for PCMCIA devices when CONFIG_PCMCIA is set at
              kernel compilation time.

       /proc/[pid]/timers (since Linux 3.10)
              A list of the POSIX timers for this process.  Each timer is
              listed with a line that started with the string "ID:".  For
              example:

                  ID: 1
                  signal: 60/00007fff86e452a8
                  notify: signal/pid.2634
                  ClockID: 0
                  ID: 0
                  signal: 60/00007fff86e452a8
                  notify: signal/pid.2634
                  ClockID: 1

              The lines shown for each timer have the following meanings:

              ID     The ID for this timer.  This is not the same as the
                     timer ID returned by timer_create(2); rather, it is the
                     same kernel-internal ID that is available via the
                     si_timerid field of the siginfo_t structure (see
                     sigaction(2)).

              signal This is the signal number that this timer uses to
                     deliver notifications followed by a slash, and then the
                     sigev_value.sival_ptr value supplied to the signal
                     handler.  Valid only for timers that notify via a
                     signal.

              notify The part before the slash specifies the mechanism that
                     this timer uses to deliver notifications, and is one of
                     "thread", "signal", or "none".  Immediately following
                     the slash is either the string "tid" for timers with
                     SIGEV_THREAD_ID notification, or "pid" for timers that
                     notify by other mechanisms.  Following the "." is the
                     PID of the process that will be delivered a signal if
                     the timer delivers notifications via a signal.

              ClockID
                     This field identifies the clock that the timer uses for
                     measuring time.  For most clocks, this is a number that
                     matches one of the user-space CLOCK_* constants exposed
                     via <time.h>.  CLOCK_PROCESS_CPUTIME_ID timers display
                     with a value of -6 in this field.
                     CLOCK_THREAD_CPUTIME_ID timers display with a value of
                     -2 in this field.

       /proc/bus/pccard/drivers

       /proc/bus/pci
              Contains various bus subdirectories and pseudo-files
              containing information about PCI busses, installed devices,
              and device drivers.  Some of these files are not ASCII.

       /proc/bus/pci/devices
              Information about PCI devices.  They may be accessed through
              lspci(8) and setpci(8).

       /proc/cmdline
              Arguments passed to the Linux kernel at boot time.  Often done
              via a boot manager such as lilo(8) or grub(8).

       /proc/config.gz (since Linux 2.6)
              This file exposes the configuration options that were used to
              build the currently running kernel, in the same format as they
              would be shown in the .config file that resulted when
              configuring the kernel (using make xconfig, make config, or
              similar).  The file contents are compressed; view or search
              them using zcat(1) and zgrep(1).  As long as no changes have
              been made to the following file, the contents of
              /proc/config.gz are the same as those provided by :

                  cat /lib/modules/$(uname -r)/build/.config

              /proc/config.gz is provided only if the kernel is configured
              with CONFIG_IKCONFIG_PROC.

       /proc/cpuinfo
              This is a collection of CPU and system architecture dependent
              items, for each supported architecture a different list.  Two
              common entries are processor which gives CPU number and
              bogomips; a system constant that is calculated during kernel
              initialization.  SMP machines have information for each CPU.
              The lscpu(1) command gathers its information from this file.

       /proc/devices
              Text listing of major numbers and device groups.  This can be
              used by MAKEDEV scripts for consistency with the kernel.

       /proc/diskstats (since Linux 2.5.69)
              This file contains disk I/O statistics for each disk device.
              See the Linux kernel source file Documentation/iostats.txt for
              further information.

       /proc/dma
              This is a list of the registered ISA DMA (direct memory
              access) channels in use.

       /proc/driver
              Empty subdirectory.

       /proc/execdomains
              List of the execution domains (ABI personalities).

       /proc/fb
              Frame buffer information when CONFIG_FB is defined during
              kernel compilation.

       /proc/filesystems
              A text listing of the filesystems which are supported by the
              kernel, namely filesystems which were compiled into the kernel
              or whose kernel modules are currently loaded.  (See also
              filesystems(5).)  If a filesystem is marked with "nodev", this
              means that it does not require a block device to be mounted
              (e.g., virtual filesystem, network filesystem).

              Incidentally, this file may be used by mount(8) when no
              filesystem is specified and it didn't manage to determine the
              filesystem type.  Then filesystems contained in this file are
              tried (excepted those that are marked with "nodev").

       /proc/fs
              Contains subdirectories that in turn contain files with
              information about (certain) mounted filesystems.

       /proc/ide
              This directory exists on systems with the IDE bus.  There are
              directories for each IDE channel and attached device.  Files
              include:

                  cache              buffer size in KB
                  capacity           number of sectors
                  driver             driver version
                  geometry           physical and logical geometry
                  identify           in hexadecimal
                  media              media type
                  model              manufacturer's model number
                  settings           drive settings
                  smart_thresholds   in hexadecimal
                  smart_values       in hexadecimal

              The hdparm(8) utility provides access to this information in a
              friendly format.

       /proc/interrupts
              This is used to record the number of interrupts per CPU per IO
              device.  Since Linux 2.6.24, for the i386 and x86_64
              architectures, at least, this also includes interrupts
              internal to the system (that is, not associated with a device
              as such), such as NMI (nonmaskable interrupt), LOC (local
              timer interrupt), and for SMP systems, TLB (TLB flush
              interrupt), RES (rescheduling interrupt), CAL (remote function
              call interrupt), and possibly others.  Very easy to read
              formatting, done in ASCII.

       /proc/iomem
              I/O memory map in Linux 2.4.

       /proc/ioports
              This is a list of currently registered Input-Output port
              regions that are in use.

       /proc/kallsyms (since Linux 2.5.71)
              This holds the kernel exported symbol definitions used by the
              modules(X) tools to dynamically link and bind loadable
              modules.  In Linux 2.5.47 and earlier, a similar file with
              slightly different syntax was named ksyms.

       /proc/kcore
              This file represents the physical memory of the system and is
              stored in the ELF core file format.  With this pseudo-file,
              and an unstripped kernel (/usr/src/linux/vmlinux) binary, GDB
              can be used to examine the current state of any kernel data
              structures.

              The total length of the file is the size of physical memory
              (RAM) plus 4KB.

       /proc/kmsg
              This file can be used instead of the syslog(2) system call to
              read kernel messages.  A process must have superuser
              privileges to read this file, and only one process should read
              this file.  This file should not be read if a syslog process
              is running which uses the syslog(2) system call facility to
              log kernel messages.

              Information in this file is retrieved with the dmesg(1)
              program.

       /proc/ksyms (Linux 1.1.23-2.5.47)
              See /proc/kallsyms.

       /proc/loadavg
              The first three fields in this file are load average figures
              giving the number of jobs in the run queue (state R) or
              waiting for disk I/O (state D) averaged over 1, 5, and 15
              minutes.  They are the same as the load average numbers given
              by uptime(1) and other programs.  The fourth field consists of
              two numbers separated by a slash (/).  The first of these is
              the number of currently runnable kernel scheduling entities
              (processes, threads).  The value after the slash is the number
              of kernel scheduling entities that currently exist on the
              system.  The fifth field is the PID of the process that was
              most recently created on the system.

       /proc/locks
              This file shows current file locks (flock(2) and fcntl(2)) and
              leases (fcntl(2)).

       /proc/malloc (only up to and including Linux 2.2)
              This file is present only if CONFIG_DEBUG_MALLOC was defined
              during compilation.

       /proc/meminfo
              This file reports statistics about memory usage on the system.
              It is used by free(1) to report the amount of free and used
              memory (both physical and swap) on the system as well as the
              shared memory and buffers used by the kernel.  Each line of
              the file consists of a parameter name, followed by a colon,
              the value of the parameter, and an option unit of measurement
              (e.g., "kB").  The list below describes the parameter names
              and the format specifier required to read the field value.
              Except as noted below, all of the fields have been present
              since at least Linux 2.6.0.  Some fields are displayed only if
              the kernel was configured with various options; those
              dependencies are noted in the list.

              MemTotal %lu
                     Total usable RAM (i.e., physical RAM minus a few
                     reserved bits and the kernel binary code).

              MemFree %lu
                     The sum of LowFree+HighFree.

              Buffers %lu
                     Relatively temporary storage for raw disk blocks that
                     shouldn't get tremendously large (20MB or so).

              Cached %lu
                     In-memory cache for files read from the disk (the page
                     cache).  Doesn't include SwapCached.

              SwapCached %lu
                     Memory that once was swapped out, is swapped back in
                     but still also is in the swap file.  (If memory
                     pressure is high, these pages don't need to be swapped
                     out again because they are already in the swap file.
                     This saves I/O.)

              Active %lu
                     Memory that has been used more recently and usually not
                     reclaimed unless absolutely necessary.

              Inactive %lu
                     Memory which has been less recently used.  It is more
                     eligible to be reclaimed for other purposes.

              Active(anon) %lu (since Linux 2.6.28)
                     [To be documented.]

              Inactive(anon) %lu (since Linux 2.6.28)
                     [To be documented.]

              Active(file) %lu (since Linux 2.6.28)
                     [To be documented.]

              Inactive(file) %lu (since Linux 2.6.28)
                     [To be documented.]

              Unevictable %lu (since Linux 2.6.28)
                     (From Linux 2.6.28 to 2.6.30, CONFIG_UNEVICTABLE_LRU
                     was required.)  [To be documented.]

              Mlocked %lu (since Linux 2.6.28)
                     (From Linux 2.6.28 to 2.6.30, CONFIG_UNEVICTABLE_LRU
                     was required.)  [To be documented.]

              HighTotal %lu
                     (Starting with Linux 2.6.19, CONFIG_HIGHMEM is
                     required.)  Total amount of highmem.  Highmem is all
                     memory above ~860MB of physical memory.  Highmem areas
                     are for use by user-space programs, or for the page
                     cache.  The kernel must use tricks to access this
                     memory, making it slower to access than lowmem.

              HighFree %lu
                     (Starting with Linux 2.6.19, CONFIG_HIGHMEM is
                     required.)  Amount of free highmem.

              LowTotal %lu
                     (Starting with Linux 2.6.19, CONFIG_HIGHMEM is
                     required.)  Total amount of lowmem.  Lowmem is memory
                     which can be used for everything that highmem can be
                     used for, but it is also available for the kernel's use
                     for its own data structures.  Among many other things,
                     it is where everything from Slab is allocated.  Bad
                     things happen when you're out of lowmem.

              LowFree %lu
                     (Starting with Linux 2.6.19, CONFIG_HIGHMEM is
                     required.)  Amount of free lowmem.

              MmapCopy %lu (since Linux 2.6.29)
                     (CONFIG_MMU is required.)  [To be documented.]

              SwapTotal %lu
                     Total amount of swap space available.

              SwapFree %lu
                     Amount of swap space that is currently unused.

              Dirty %lu
                     Memory which is waiting to get written back to the
                     disk.

              Writeback %lu
                     Memory which is actively being written back to the
                     disk.

              AnonPages %lu (since Linux 2.6.18)
                     Non-file backed pages mapped into user-space page
                     tables.

              Mapped %lu
                     Files which have been mapped into memory (with
                     mmap(2)), such as libraries.

              Shmem %lu (since Linux 2.6.32)
                     [To be documented.]

              Slab %lu
                     In-kernel data structures cache.

              SReclaimable %lu (since Linux 2.6.19)
                     Part of Slab, that might be reclaimed, such as caches.

              SUnreclaim %lu (since Linux 2.6.19)
                     Part of Slab, that cannot be reclaimed on memory
                     pressure.

              KernelStack %lu (since Linux 2.6.32)
                     Amount of memory allocated to kernel stacks.

              PageTables %lu (since Linux 2.6.18)
                     Amount of memory dedicated to the lowest level of page
                     tables.

              Quicklists %lu (since Linux 2.6.27)
                     (CONFIG_QUICKLIST is required.)  [To be documented.]

              NFS_Unstable %lu (since Linux 2.6.18)
                     NFS pages sent to the server, but not yet committed to
                     stable storage.

              Bounce %lu (since Linux 2.6.18)
                     Memory used for block device "bounce buffers".

              WritebackTmp %lu (since Linux 2.6.26)
                     Memory used by FUSE for temporary writeback buffers.

              CommitLimit %lu (since Linux 2.6.10)
                     Based on the overcommit ratio ('vm.overcommit_ratio'),
                     this is the total amount of memory currently available
                     to be allocated on the system.  This limit is adhered
                     to only if strict overcommit accounting is enabled
                     (mode 2 in /proc/sys/vm/overcommit_ratio).  The
                     CommitLimit is calculated using the following formula:

                         CommitLimit =
                             ([total RAM pages] - [total huge TLB pages]) *
                             overcommit_ratio / 100 + [total swap pages]

                     For example, on a system with 1GB of physical RAM and
                     7GB of swap with a overcommit_ratio of 30, this formula
                     yields a CommitLimit of 7.3GB.  For more details, see
                     the memory overcommit documentation in the kernel
                     source file Documentation/vm/overcommit-accounting.

              Committed_AS %lu
                     The amount of memory presently allocated on the system.
                     The committed memory is a sum of all of the memory
                     which has been allocated by processes, even if it has
                     not been "used" by them as of yet.  A process which
                     allocates 1GB of memory (using malloc(3) or similar),
                     but touches only 300MB of that memory will show up as
                     using only 300MB of memory even if it has the address
                     space allocated for the entire 1GB.  This 1GB is memory
                     which has been "committed" to by the VM and can be used
                     at any time by the allocating application.  With strict
                     overcommit enabled on the system (mode 2
                     /proc/sys/vm/overcommit_memory), allocations which
                     would exceed the CommitLimit (detailed above) will not
                     be permitted.  This is useful if one needs to guarantee
                     that processes will not fail due to lack of memory once
                     that memory has been successfully allocated.

              VmallocTotal %lu
                     Total size of vmalloc memory area.

              VmallocUsed %lu
                     Amount of vmalloc area which is used.

              VmallocChunk %lu
                     Largest contiguous block of vmalloc area which is free.

              HardwareCorrupted %lu (since Linux 2.6.32)
                     (CONFIG_MEMORY_FAILURE is required.)  [To be
                     documented.]

              AnonHugePages %lu (since Linux 2.6.38)
                     (CONFIG_TRANSPARENT_HUGEPAGE is required.)  Non-file
                     backed huge pages mapped into user-space page tables.

              HugePages_Total %lu
                     (CONFIG_HUGETLB_PAGE is required.)  The size of the
                     pool of huge pages.

              HugePages_Free %lu
                     (CONFIG_HUGETLB_PAGE is required.)  The number of huge
                     pages in the pool that are not yet allocated.

              HugePages_Rsvd %lu (since Linux 2.6.17)
                     (CONFIG_HUGETLB_PAGE is required.)  This is the number
                     of huge pages for which a commitment to allocate from
                     the pool has been made, but no allocation has yet been
                     made.  These reserved huge pages guarantee that an
                     application will be able to allocate a huge page from
                     the pool of huge pages at fault time.

              HugePages_Surp %lu (since Linux 2.6.24)
                     (CONFIG_HUGETLB_PAGE is required.)  This is the number
                     of huge pages in the pool above the value in
                     /proc/sys/vm/nr_hugepages.  The maximum number of
                     surplus huge pages is controlled by
                     /proc/sys/vm/nr_overcommit_hugepages.

              Hugepagesize %lu
                     (CONFIG_HUGETLB_PAGE is required.)  The size of huge
                     pages.

       /proc/modules
              A text list of the modules that have been loaded by the
              system.  See also lsmod(8).

       /proc/mounts
              Before kernel 2.4.19, this file was a list of all the
              filesystems currently mounted on the system.  With the
              introduction of per-process mount namespaces in Linux 2.4.19,
              this file became a link to /proc/self/mounts, which lists the
              mount points of the process's own mount namespace.  The format
              of this file is documented in fstab(5).

       /proc/mtrr
              Memory Type Range Registers.  See the Linux kernel source file
              Documentation/mtrr.txt for details.

       /proc/net
              various net pseudo-files, all of which give the status of some
              part of the networking layer.  These files contain ASCII
              structures and are, therefore, readable with cat(1).  However,
              the standard netstat(8) suite provides much cleaner access to
              these files.

       /proc/net/arp
              This holds an ASCII readable dump of the kernel ARP table used
              for address resolutions.  It will show both dynamically
              learned and preprogrammed ARP entries.  The format is:

        IP address     HW type   Flags     HW address          Mask   Device
        192.168.0.50   0x1       0x2       00:50:BF:25:68:F3   *      eth0
        192.168.0.250  0x1       0xc       00:00:00:00:00:00   *      eth0

              Here "IP address" is the IPv4 address of the machine and the
              "HW type" is the hardware type of the address from RFC 826.
              The flags are the internal flags of the ARP structure (as
              defined in /usr/include/linux/if_arp.h) and the "HW address"
              is the data link layer mapping for that IP address if it is
              known.

       /proc/net/dev
              The dev pseudo-file contains network device status
              information.  This gives the number of received and sent
              packets, the number of errors and collisions and other basic
              statistics.  These are used by the ifconfig(8) program to
              report device status.  The format is:

 Inter-|   Receive                                                |  Transmit
  face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
     lo: 2776770   11307    0    0    0     0          0         0  2776770   11307    0    0    0     0       0          0
   eth0: 1215645    2751    0    0    0     0          0         0  1782404    4324    0    0    0   427       0          0
   ppp0: 1622270    5552    1    0    0     0          0         0   354130    5669    0    0    0     0       0          0
   tap0:    7714      81    0    0    0     0          0         0     7714      81    0    0    0     0       0          0

       /proc/net/dev_mcast
              Defined in /usr/src/linux/net/core/dev_mcast.c:
                   indx interface_name  dmi_u dmi_g dmi_address
                   2    eth0            1     0     01005e000001
                   3    eth1            1     0     01005e000001
                   4    eth2            1     0     01005e000001

       /proc/net/igmp
              Internet Group Management Protocol.  Defined in
              /usr/src/linux/net/core/igmp.c.

       /proc/net/rarp
              This file uses the same format as the arp file and contains
              the current reverse mapping database used to provide rarp(8)
              reverse address lookup services.  If RARP is not configured
              into the kernel, this file will not be present.

       /proc/net/raw
              Holds a dump of the RAW socket table.  Much of the information
              is not of use apart from debugging.  The "sl" value is the
              kernel hash slot for the socket, the "local_address" is the
              local address and protocol number pair.  "St" is the internal
              status of the socket.  The "tx_queue" and "rx_queue" are the
              outgoing and incoming data queue in terms of kernel memory
              usage.  The "tr", "tm->when", and "rexmits" fields are not
              used by RAW.  The "uid" field holds the effective UID of the
              creator of the socket.

       /proc/net/snmp
              This file holds the ASCII data needed for the IP, ICMP, TCP,
              and UDP management information bases for an SNMP agent.

       /proc/net/tcp
              Holds a dump of the TCP socket table.  Much of the information
              is not of use apart from debugging.  The "sl" value is the
              kernel hash slot for the socket, the "local_address" is the
              local address and port number pair.  The "rem_address" is the
              remote address and port number pair (if connected).  "St" is
              the internal status of the socket.  The "tx_queue" and
              "rx_queue" are the outgoing and incoming data queue in terms
              of kernel memory usage.  The "tr", "tm->when", and "rexmits"
              fields hold internal information of the kernel socket state
              and are only useful for debugging.  The "uid" field holds the
              effective UID of the creator of the socket.

       /proc/net/udp
              Holds a dump of the UDP socket table.  Much of the information
              is not of use apart from debugging.  The "sl" value is the
              kernel hash slot for the socket, the "local_address" is the
              local address and port number pair.  The "rem_address" is the
              remote address and port number pair (if connected). "St" is
              the internal status of the socket.  The "tx_queue" and
              "rx_queue" are the outgoing and incoming data queue in terms
              of kernel memory usage.  The "tr", "tm->when", and "rexmits"
              fields are not used by UDP.  The "uid" field holds the
              effective UID of the creator of the socket.  The format is:

 sl  local_address rem_address   st tx_queue rx_queue tr rexmits  tm->when uid
  1: 01642C89:0201 0C642C89:03FF 01 00000000:00000001 01:000071BA 00000000 0
  1: 00000000:0801 00000000:0000 0A 00000000:00000000 00:00000000 6F000100 0
  1: 00000000:0201 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0

       /proc/net/unix
              Lists the UNIX domain sockets present within the system and
              their status.  The format is:
              Num RefCount Protocol Flags    Type St Path
               0: 00000002 00000000 00000000 0001 03
               1: 00000001 00000000 00010000 0001 01 /dev/printer

              Here "Num" is the kernel table slot number, "RefCount" is the
              number of users of the socket, "Protocol" is currently always
              0, "Flags" represent the internal kernel flags holding the
              status of the socket.  Currently, type is always "1" (UNIX
              domain datagram sockets are not yet supported in the kernel).
              "St" is the internal state of the socket and Path is the bound
              path (if any) of the socket.

       /proc/partitions
              Contains the major and minor numbers of each partition as well
              as the number of 1024-byte blocks and the partition name.

       /proc/pci
              This is a listing of all PCI devices found during kernel
              initialization and their configuration.

              This file has been deprecated in favor of a new /proc
              interface for PCI (/proc/bus/pci).  It became optional in
              Linux 2.2 (available with CONFIG_PCI_OLD_PROC set at kernel
              compilation).  It became once more nonoptionally enabled in
              Linux 2.4.  Next, it was deprecated in Linux 2.6 (still
              available with CONFIG_PCI_LEGACY_PROC set), and finally
              removed altogether since Linux 2.6.17.

       /proc/profile (since Linux 2.4)
              This file is present only if the kernel was booted with the
              profile=1 command-line option.  It exposes kernel profiling
              information in a binary format for use by readprofile(1).
              Writing (e.g., an empty string) to this file resets the
              profiling counters; on some architectures, writing a binary
              integer "profiling multiplier" of size sizeof(int) sets the
              profiling interrupt frequency.

       /proc/scsi
              A directory with the scsi mid-level pseudo-file and various
              SCSI low-level driver directories, which contain a file for
              each SCSI host in this system, all of which give the status of
              some part of the SCSI IO subsystem.  These files contain ASCII
              structures and are, therefore, readable with cat(1).

              You can also write to some of the files to reconfigure the
              subsystem or switch certain features on or off.

       /proc/scsi/scsi
              This is a listing of all SCSI devices known to the kernel.
              The listing is similar to the one seen during bootup.  scsi
              currently supports only the add-single-device command which
              allows root to add a hotplugged device to the list of known
              devices.

              The command

                  echo 'scsi add-single-device 1 0 5 0' > /proc/scsi/scsi

              will cause host scsi1 to scan on SCSI channel 0 for a device
              on ID 5 LUN 0.  If there is already a device known on this
              address or the address is invalid, an error will be returned.

       /proc/scsi/[drivername]
              [drivername] can currently be NCR53c7xx, aha152x, aha1542,
              aha1740, aic7xxx, buslogic, eata_dma, eata_pio, fdomain,
              in2000, pas16, qlogic, scsi_debug, seagate, t128, u15-24f,
              ultrastore, or wd7000.  These directories show up for all
              drivers that registered at least one SCSI HBA.  Every
              directory contains one file per registered host.  Every host-
              file is named after the number the host was assigned during
              initialization.

              Reading these files will usually show driver and host
              configuration, statistics, and so on.

              Writing to these files allows different things on different
              hosts.  For example, with the latency and nolatency commands,
              root can switch on and off command latency measurement code in
              the eata_dma driver.  With the lockup and unlock commands,
              root can control bus lockups simulated by the scsi_debug
              driver.

       /proc/self
              This directory refers to the process accessing the /proc
              filesystem, and is identical to the /proc directory named by
              the process ID of the same process.

       /proc/slabinfo
              Information about kernel caches.  Since Linux 2.6.16 this file
              is present only if the CONFIG_SLAB kernel configuration option
              is enabled.  The columns in /proc/slabinfo are:

                  cache-name
                  num-active-objs
                  total-objs
                  object-size
                  num-active-slabs
                  total-slabs
                  num-pages-per-slab

              See slabinfo(5) for details.

       /proc/stat
              kernel/system statistics.  Varies with architecture.  Common
              entries include:

              cpu  3357 0 4313 1362393
                     The amount of time, measured in units of USER_HZ
                     (1/100ths of a second on most architectures, use
                     sysconf(_SC_CLK_TCK) to obtain the right value), that
                     the system spent in various states:

                     user   (1) Time spent in user mode.

                     nice   (2) Time spent in user mode with low priority
                            (nice).

                     system (3) Time spent in system mode.

                     idle   (4) Time spent in the idle task.  This value
                            should be USER_HZ times the second entry in the
                            /proc/uptime pseudo-file.

                     iowait (since Linux 2.5.41)
                            (5) Time waiting for I/O to complete.

                     irq (since Linux 2.6.0-test4)
                            (6) Time servicing interrupts.

                     softirq (since Linux 2.6.0-test4)
                            (7) Time servicing softirqs.

                     steal (since Linux 2.6.11)
                            (8) Stolen time, which is the time spent in
                            other operating systems when running in a
                            virtualized environment

                     guest (since Linux 2.6.24)
                            (9) Time spent running a virtual CPU for guest
                            operating systems under the control of the Linux
                            kernel.

                     guest_nice (since Linux 2.6.33)
                            (10) Time spent running a niced guest (virtual
                            CPU for guest operating systems under the
                            control of the Linux kernel).

              page 5741 1808
                     The number of pages the system paged in and the number
                     that were paged out (from disk).

              swap 1 0
                     The number of swap pages that have been brought in and
                     out.

              intr 1462898
                     This line shows counts of interrupts serviced since
                     boot time, for each of the possible system interrupts.
                     The first column is the total of all interrupts
                     serviced including unnumbered architecture specific
                     interrupts; each subsequent column is the total for
                     that particular numbered interrupt.  Unnumbered
                     interrupts are not shown, only summed into the total.

              disk_io: (2,0):(31,30,5764,1,2) (3,0):...
                     (major,disk_idx):(noinfo, read_io_ops, blks_read,
                     write_io_ops, blks_written)
                     (Linux 2.4 only)

              ctxt 115315
                     The number of context switches that the system
                     underwent.

              btime 769041601
                     boot time, in seconds since the Epoch, 1970-01-01
                     00:00:00 +0000 (UTC).

              processes 86031
                     Number of forks since boot.

              procs_running 6
                     Number of processes in runnable state.  (Linux 2.5.45
                     onward.)

              procs_blocked 2
                     Number of processes blocked waiting for I/O to
                     complete.  (Linux 2.5.45 onward.)

       /proc/swaps
              Swap areas in use.  See also swapon(8).

       /proc/sys
              This directory (present since 1.3.57) contains a number of
              files and subdirectories corresponding to kernel variables.
              These variables can be read and sometimes modified using the
              /proc filesystem, and the (deprecated) sysctl(2) system call.

       /proc/sys/abi (since Linux 2.4.10)
              This directory may contain files with application binary
              information.  See the Linux kernel source file
              Documentation/sysctl/abi.txt for more information.

       /proc/sys/debug
              This directory may be empty.

       /proc/sys/dev
              This directory contains device-specific information (e.g.,
              dev/cdrom/info).  On some systems, it may be empty.

       /proc/sys/fs
              This directory contains the files and subdirectories for
              kernel variables related to filesystems.

       /proc/sys/fs/binfmt_misc
              Documentation for files in this directory can be found in the
              Linux kernel sources in Documentation/binfmt_misc.txt.

       /proc/sys/fs/dentry-state (since Linux 2.2)
              This file contains information about the status of the
              directory cache (dcache).  The file contains six numbers,
              nr_dentry, nr_unused, age_limit (age in seconds), want_pages
              (pages requested by system) and two dummy values.

              * nr_dentry is the number of allocated dentries (dcache
                entries).  This field is unused in Linux 2.2.

              * nr_unused is the number of unused dentries.

              * age_limit is the age in seconds after which dcache entries
                can be reclaimed when memory is short.

              * want_pages is nonzero when the kernel has called
                shrink_dcache_pages() and the dcache isn't pruned yet.

       /proc/sys/fs/dir-notify-enable
              This file can be used to disable or enable the dnotify
              interface described in fcntl(2) on a system-wide basis.  A
              value of 0 in this file disables the interface, and a value of
              1 enables it.

       /proc/sys/fs/dquot-max
              This file shows the maximum number of cached disk quota
              entries.  On some (2.4) systems, it is not present.  If the
              number of free cached disk quota entries is very low and you
              have some awesome number of simultaneous system users, you
              might want to raise the limit.

       /proc/sys/fs/dquot-nr
              This file shows the number of allocated disk quota entries and
              the number of free disk quota entries.

       /proc/sys/fs/epoll (since Linux 2.6.28)
              This directory contains the file max_user_watches, which can
              be used to limit the amount of kernel memory consumed by the
              epoll interface.  For further details, see epoll(7).

       /proc/sys/fs/file-max
              This file defines a system-wide limit on the number of open
              files for all processes.  (See also setrlimit(2), which can be
              used by a process to set the per-process limit, RLIMIT_NOFILE,
              on the number of files it may open.)  If you get lots of error
              messages in the kernel log about running out of file handles
              (look for "VFS: file-max limit <number> reached"), try
              increasing this value:

                  echo 100000 > /proc/sys/fs/file-max

              The kernel constant NR_OPEN imposes an upper limit on the
              value that may be placed in file-max.

              Privileged processes (CAP_SYS_ADMIN) can override the file-max
              limit.

       /proc/sys/fs/file-nr
              This (read-only) file contains three numbers: the number of
              allocated file handles (i.e., the number of files presently
              opened); the number of free file handles; and the maximum
              number of file handles (i.e., the same value as
              /proc/sys/fs/file-max).  If the number of allocated file
              handles is close to the maximum, you should consider
              increasing the maximum.  Before Linux 2.6, the kernel
              allocated file handles dynamically, but it didn't free them
              again.  Instead the free file handles were kept in a list for
              reallocation; the "free file handles" value indicates the size
              of that list.  A large number of free file handles indicates
              that there was a past peak in the usage of open file handles.
              Since Linux 2.6, the kernel does deallocate freed file
              handles, and the "free file handles" value is always zero.

       /proc/sys/fs/inode-max (only present until Linux 2.2)
              This file contains the maximum number of in-memory inodes.
              This value should be 3-4 times larger than the value in file-
              max, since stdin, stdout and network sockets also need an
              inode to handle them.  When you regularly run out of inodes,
              you need to increase this value.

              Starting with Linux 2.4, there is no longer a static limit on
              the number of inodes, and this file is removed.

       /proc/sys/fs/inode-nr
              This file contains the first two values from inode-state.

       /proc/sys/fs/inode-state
              This file contains seven numbers: nr_inodes, nr_free_inodes,
              preshrink, and four dummy values (always zero).

              nr_inodes is the number of inodes the system has allocated.
              nr_free_inodes represents the number of free inodes.

              preshrink is nonzero when the nr_inodes > inode-max and the
              system needs to prune the inode list instead of allocating
              more; since Linux 2.4, this field is a dummy value (always
              zero).

       /proc/sys/fs/inotify (since Linux 2.6.13)
              This directory contains files max_queued_events,
              max_user_instances, and max_user_watches, that can be used to
              limit the amount of kernel memory consumed by the inotify
              interface.  For further details, see inotify(7).

       /proc/sys/fs/lease-break-time
              This file specifies the grace period that the kernel grants to
              a process holding a file lease (fcntl(2)) after it has sent a
              signal to that process notifying it that another process is
              waiting to open the file.  If the lease holder does not remove
              or downgrade the lease within this grace period, the kernel
              forcibly breaks the lease.

       /proc/sys/fs/leases-enable
              This file can be used to enable or disable file leases
              (fcntl(2)) on a system-wide basis.  If this file contains the
              value 0, leases are disabled.  A nonzero value enables leases.

       /proc/sys/fs/mqueue (since Linux 2.6.6)
              This directory contains files msg_max, msgsize_max, and
              queues_max, controlling the resources used by POSIX message
              queues.  See mq_overview(7) for details.

       /proc/sys/fs/overflowgid and /proc/sys/fs/overflowuid
              These files allow you to change the value of the fixed UID and
              GID.  The default is 65534.  Some filesystems support only
              16-bit UIDs and GIDs, although in Linux UIDs and GIDs are 32
              bits.  When one of these filesystems is mounted with writes
              enabled, any UID or GID that would exceed 65535 is translated
              to the overflow value before being written to disk.

       /proc/sys/fs/pipe-max-size (since Linux 2.6.35)
              The value in this file defines an upper limit for raising the
              capacity of a pipe using the fcntl(2) F_SETPIPE_SZ operation.
              This limit applies only to unprivileged processes.  The
              default value for this file is 1,048,576.  The value assigned
              to this file may be rounded upward, to reflect the value
              actually employed for a convenient implementation.  To
              determine the rounded-up value, display the contents of this
              file after assigning a value to it.  The minimum value that
              can be assigned to this file is the system page size.

       /proc/sys/fs/protected_hardlinks (since Linux 3.6)
              When the value in this file is 0, no restrictions are placed
              on the creation of hard links (i.e., this is the historical
              behavior before Linux 3.6).  When the value in this file is 1,
              a hard link can be created to a target file only if one of the
              following conditions is true:

              *  The caller has the CAP_FOWNER capability.

              *  The filesystem UID of the process creating the link matches
                 the owner (UID) of the target file (as described in
                 credentials(7), a process's filesystem UID is normally the
                 same as its effective UID).

              *  All of the following conditions are true:

                  ·  the target is a regular file;

                  ·  the target file does not have its set-user-ID
                     permission bit enabled;

                  ·  the target file does not have both its set-group-ID and
                     group-executable permission bits enabled; and

                  ·  the caller has permission to read and write the target
                     file (either via the file's permissions mask or because
                     it has suitable capabilities).

              The default value in this file is 0.  Setting the value to 1
              prevents a longstanding class of security issues caused by
              hard-link-based time-of-check, time-of-use races, most
              commonly seen in world-writable directories such as /tmp.  The
              common method of exploiting this flaw is to cross privilege
              boundaries when following a given hard link (i.e., a root
              process follows a hard link created by another user).
              Additionally, on systems without separated partitions, this
              stops unauthorized users from "pinning" vulnerable set-user-ID
              and set-group-ID files against being upgraded by the
              administrator, or linking to special files.

       /proc/sys/fs/protected_symlinks (since Linux 3.6)
              When the value in this file is 0, no restrictions are placed
              on following symbolic links (i.e., this is the historical
              behavior before Linux 3.6).  When the value in this file is 1,
              symbolic links are followed only in the following
              circumstances:

              *  the filesystem UID of the process following the link
                 matches the owner (UID) of the symbolic link (as described
                 in credentials(7), a process's filesystem UID is normally
                 the same as its effective UID);

              *  the link is not in a sticky world-writable directory; or

              *  the symbolic link and its parent directory have the same
                 owner (UID)

              A system call that fails to follow a symbolic link because of
              the above restrictions returns the error EACCES in errno.

              The default value in this file is 0.  Setting the value to 1
              avoids a longstanding class of security issues based on time-
              of-check, time-of-use races when accessing symbolic links.

       /proc/sys/fs/suid_dumpable (since Linux 2.6.13)
              The value in this file determines whether core dump files are
              produced for set-user-ID or otherwise protected/tainted
              binaries.  Three different integer values can be specified:

              0 (default)
                     This provides the traditional (pre-Linux 2.6.13)
                     behavior.  A core dump will not be produced for a
                     process which has changed credentials (by calling
                     seteuid(2), setgid(2), or similar, or by executing a
                     set-user-ID or set-group-ID program) or whose binary
                     does not have read permission enabled.

              1 ("debug")
                     All processes dump core when possible.  The core dump
                     is owned by the filesystem user ID of the dumping
                     process and no security is applied.  This is intended
                     for system debugging situations only.  Ptrace is
                     unchecked.

              2 ("suidsafe")
                     Any binary which normally would not be dumped (see "0"
                     above) is dumped readable by root only.  This allows
                     the user to remove the core dump file but not to read
                     it.  For security reasons core dumps in this mode will
                     not overwrite one another or other files.  This mode is
                     appropriate when administrators are attempting to debug
                     problems in a normal environment.

                     Additionally, since Linux 3.6,
                     /proc/sys/kernel/core_pattern must either be an
                     absolute pathname or a pipe command, as detailed in
                     core(5).  Warnings will be written to the kernel log if
                     core_pattern does not follow these rules, and no core
                     dump will be produced.

       /proc/sys/fs/super-max
              This file controls the maximum number of superblocks, and thus
              the maximum number of mounted filesystems the kernel can have.
              You need increase only super-max if you need to mount more
              filesystems than the current value in super-max allows you to.

       /proc/sys/fs/super-nr
              This file contains the number of filesystems currently
              mounted.

       /proc/sys/kernel
              This directory contains files controlling a range of kernel
              parameters, as described below.

       /proc/sys/kernel/acct
              This file contains three numbers: highwater, lowwater, and
              frequency.  If BSD-style process accounting is enabled, these
              values control its behavior.  If free space on filesystem
              where the log lives goes below lowwater percent, accounting
              suspends.  If free space gets above highwater percent,
              accounting resumes.  frequency determines how often the kernel
              checks the amount of free space (value is in seconds).
              Default values are 4, 2 and 30.  That is, suspend accounting
              if 2% or less space is free; resume it if 4% or more space is
              free; consider information about amount of free space valid
              for 30 seconds.

       /proc/sys/kernel/cap_last_cap (since Linux 3.2)
              See capabilities(7).

       /proc/sys/kernel/cap-bound (from Linux 2.2 to 2.6.24)
              This file holds the value of the kernel capability bounding
              set (expressed as a signed decimal number).  This set is ANDed
              against the capabilities permitted to a process during
              execve(2).  Starting with Linux 2.6.25, the system-wide
              capability bounding set disappeared, and was replaced by a
              per-thread bounding set; see capabilities(7).

       /proc/sys/kernel/core_pattern
              See core(5).

       /proc/sys/kernel/core_uses_pid
              See core(5).

       /proc/sys/kernel/ctrl-alt-del
              This file controls the handling of Ctrl-Alt-Del from the
              keyboard.  When the value in this file is 0, Ctrl-Alt-Del is
              trapped and sent to the init(8) program to handle a graceful
              restart.  When the value is greater than zero, Linux's
              reaction to a Vulcan Nerve Pinch (tm) will be an immediate
              reboot, without even syncing its dirty buffers.  Note: when a
              program (like dosemu) has the keyboard in "raw" mode, the
              ctrl-alt-del is intercepted by the program before it ever
              reaches the kernel tty layer, and it's up to the program to
              decide what to do with it.

       /proc/sys/kernel/dmesg_restrict (since Linux 2.6.37)
              The value in this file determines who can see kernel syslog
              contents.  A value of 0 in this file imposes no restrictions.
              If the value is 1, only privileged users can read the kernel
              syslog.  (See syslog(2) for more details.)  Since Linux 3.4,
              only users with the CAP_SYS_ADMIN capability may change the
              value in this file.

       /proc/sys/kernel/domainname and /proc/sys/kernel/hostname
              can be used to set the NIS/YP domainname and the hostname of
              your box in exactly the same way as the commands domainname(1)
              and hostname(1), that is:

                  # echo 'darkstar' > /proc/sys/kernel/hostname
                  # echo 'mydomain' > /proc/sys/kernel/domainname

              has the same effect as

                  # hostname 'darkstar'
                  # domainname 'mydomain'

              Note, however, that the classic darkstar.frop.org has the
              hostname "darkstar" and DNS (Internet Domain Name Server)
              domainname "frop.org", not to be confused with the NIS
              (Network Information Service) or YP (Yellow Pages) domainname.
              These two domain names are in general different.  For a
              detailed discussion see the hostname(1) man page.

       /proc/sys/kernel/hotplug
              This file contains the path for the hotplug policy agent.  The
              default value in this file is /sbin/hotplug.

       /proc/sys/kernel/htab-reclaim
              (PowerPC only) If this file is set to a nonzero value, the
              PowerPC htab (see kernel file
              Documentation/powerpc/ppc_htab.txt) is pruned each time the
              system hits the idle loop.

       /proc/sys/kernel/kptr_restrict (since Linux 2.6.38)
              The value in this file determines whether kernel addresses are
              exposed via /proc files and other interfaces.  A value of 0 in
              this file imposes no restrictions.  If the value is 1, kernel
              pointers printed using the %pK format specifier will be
              replaced with zeros unless the user has the CAP_SYSLOG
              capability.  If the value is 2, kernel pointers printed using
              the %pK format specifier will be replaced with zeros
              regardless of the user's capabilities.  The initial default
              value for this file was 1, but the default was changed to 0 in
              Linux 2.6.39.  Since Linux 3.4, only users with the
              CAP_SYS_ADMIN capability can change the value in this file.

       /proc/sys/kernel/l2cr
              (PowerPC only) This file contains a flag that controls the L2
              cache of G3 processor boards.  If 0, the cache is disabled.
              Enabled if nonzero.

       /proc/sys/kernel/modprobe
              This file contains the path for the kernel module loader.  The
              default value is /sbin/modprobe.  The file is present only if
              the kernel is built with the CONFIG_MODULES (CONFIG_KMOD in
              Linux 2.6.26 and earlier) option enabled.  It is described by
              the Linux kernel source file Documentation/kmod.txt (present
              only in kernel 2.4 and earlier).

       /proc/sys/kernel/modules_disabled (since Linux 2.6.31)
              A toggle value indicating if modules are allowed to be loaded
              in an otherwise modular kernel.  This toggle defaults to off
              (0), but can be set true (1).  Once true, modules can be
              neither loaded nor unloaded, and the toggle cannot be set back
              to false.  The file is present only if the kernel is built
              with the CONFIG_MODULES option enabled.

       /proc/sys/kernel/msgmax (since Linux 2.2)
              This file defines a system-wide limit specifying the maximum
              number of bytes in a single message written on a System V
              message queue.

       /proc/sys/kernel/msgmni (since Linux 2.4)
              This file defines the system-wide limit on the number of
              message queue identifiers.

       /proc/sys/kernel/msgmnb (since Linux 2.2)
              This file defines a system-wide parameter used to initialize
              the msg_qbytes setting for subsequently created message
              queues.  The msg_qbytes setting specifies the maximum number
              of bytes that may be written to the message queue.

       /proc/sys/kernel/ngroups_max (since Linux 2.6.4)
              This is a read-only file that displays the upper limit on the
              number of a process's group memberships.

       /proc/sys/kernel/ostype and /proc/sys/kernel/osrelease
              These files give substrings of /proc/version.

       /proc/sys/kernel/overflowgid and /proc/sys/kernel/overflowuid
              These files duplicate the files /proc/sys/fs/overflowgid and
              /proc/sys/fs/overflowuid.

       /proc/sys/kernel/panic
              This file gives read/write access to the kernel variable
              panic_timeout.  If this is zero, the kernel will loop on a
              panic; if nonzero, it indicates that the kernel should
              autoreboot after this number of seconds.  When you use the
              software watchdog device driver, the recommended setting is
              60.

       /proc/sys/kernel/panic_on_oops (since Linux 2.5.68)
              This file controls the kernel's behavior when an oops or BUG
              is encountered.  If this file contains 0, then the system
              tries to continue operation.  If it contains 1, then the
              system delays a few seconds (to give klogd time to record the
              oops output) and then panics.  If the /proc/sys/kernel/panic
              file is also nonzero, then the machine will be rebooted.

       /proc/sys/kernel/pid_max (since Linux 2.5.34)
              This file specifies the value at which PIDs wrap around (i.e.,
              the value in this file is one greater than the maximum PID).
              PIDs greater than this value not allocated; thus, the value in
              this file also acts as a system-wide limit on the total number
              of processes and threads.  The default value for this file,
              32768, results in the same range of PIDs as on earlier
              kernels.  On 32-bit platforms, 32768 is the maximum value for
              pid_max.  On 64-bit systems, pid_max can be set to any value
              up to 2^22 (PID_MAX_LIMIT, approximately 4 million).

       /proc/sys/kernel/powersave-nap (PowerPC only)
              This file contains a flag.  If set, Linux-PPC will use the
              "nap" mode of powersaving, otherwise the "doze" mode will be
              used.

       /proc/sys/kernel/printk
              See syslog(2).

       /proc/sys/kernel/pty (since Linux 2.6.4)
              This directory contains two files relating to the number of
              UNIX 98 pseudoterminals (see pts(4)) on the system.

       /proc/sys/kernel/pty/max
              This file defines the maximum number of pseudoterminals.

       /proc/sys/kernel/pty/nr
              This read-only file indicates how many pseudoterminals are
              currently in use.

       /proc/sys/kernel/random
              This directory contains various parameters controlling the
              operation of the file /dev/random.  See random(4) for further
              information.

       /proc/sys/kernel/random/uuid (since Linux 2.4)
              Each read from this read-only file returns a randomly
              generated 128-bit UUID, as a string in the standard UUID
              format.

       /proc/sys/kernel/real-root-dev
              This file is documented in the Linux kernel source file
              Documentation/initrd.txt.

       /proc/sys/kernel/reboot-cmd (Sparc only)
              This file seems to be a way to give an argument to the SPARC
              ROM/Flash boot loader.  Maybe to tell it what to do after
              rebooting?

       /proc/sys/kernel/rtsig-max
              (Only in kernels up to and including 2.6.7; see setrlimit(2))
              This file can be used to tune the maximum number of POSIX
              real-time (queued) signals that can be outstanding in the
              system.

       /proc/sys/kernel/rtsig-nr
              (Only in kernels up to and including 2.6.7.)  This file shows
              the number POSIX real-time signals currently queued.

       /proc/sys/kernel/sched_rr_timeslice_ms (since Linux 3.9)
              See sched_rr_get_interval(2).

       /proc/sys/kernel/sched_rt_period_us (Since Linux 2.6.25)
              See sched(7).

       /proc/sys/kernel/sched_rt_runtime_us (Since Linux 2.6.25)
              See sched(7).

       /proc/sys/kernel/sem (since Linux 2.4)
              This file contains 4 numbers defining limits for System V IPC
              semaphores.  These fields are, in order:

              SEMMSL  The maximum semaphores per semaphore set.

              SEMMNS  A system-wide limit on the number of semaphores in all
                      semaphore sets.

              SEMOPM  The maximum number of operations that may be specified
                      in a semop(2) call.

              SEMMNI  A system-wide limit on the maximum number of semaphore
                      identifiers.

       /proc/sys/kernel/sg-big-buff
              This file shows the size of the generic SCSI device (sg)
              buffer.  You can't tune it just yet, but you could change it
              at compile time by editing include/scsi/sg.h and changing the
              value of SG_BIG_BUFF.  However, there shouldn't be any reason
              to change this value.

       /proc/sys/kernel/shm_rmid_forced (since Linux 3.1)
              If this file is set to 1, all System V shared memory segments
              will be marked for destruction as soon as the number of
              attached processes falls to zero; in other words, it is no
              longer possible to create shared memory segments that exist
              independently of any attached process.

              The effect is as though a shmctl(2) IPC_RMID is performed on
              all existing segments as well as all segments created in the
              future (until this file is reset to 0).  Note that existing
              segments that are attached to no process will be immediately
              destroyed when this file is set to 1.  Setting this option
              will also destroy segments that were created, but never
              attached, upon termination of the process that created the
              segment with shmget(2).

              Setting this file to 1 provides a way of ensuring that all
              System V shared memory segments are counted against the
              resource usage and resource limits (see the description of
              RLIMIT_AS in getrlimit(2)) of at least one process.

              Because setting this file to 1 produces behavior that is
              nonstandard and could also break existing applications, the
              default value in this file is 0.  Only set this file to 1 if
              you have a good understanding of the semantics of the
              applications using System V shared memory on your system.

       /proc/sys/kernel/shmall (since Linux 2.2)
              This file contains the system-wide limit on the total number
              of pages of System V shared memory.

       /proc/sys/kernel/shmmax (since Linux 2.2)
              This file can be used to query and set the run-time limit on
              the maximum (System V IPC) shared memory segment size that can
              be created.  Shared memory segments up to 1GB are now
              supported in the kernel.  This value defaults to SHMMAX.

       /proc/sys/kernel/shmmni (since Linux 2.4)
              This file specifies the system-wide maximum number of System V
              shared memory segments that can be created.

       /proc/sys/kernel/sysrq
              This file controls the functions allowed to be invoked by the
              SysRq key.  By default, the file contains 1 meaning that every
              possible SysRq request is allowed (in older kernel versions,
              SysRq was disabled by default, and you were required to
              specifically enable it at run-time, but this is not the case
              any more).  Possible values in this file are:

                 0 - disable sysrq completely
                 1 - enable all functions of sysrq
                >1 - bit mask of allowed sysrq functions, as follows:
                        2 - enable control of console logging level
                        4 - enable control of keyboard (SAK, unraw)
                        8 - enable debugging dumps of processes etc.
                       16 - enable sync command
                       32 - enable remount read-only
                       64 - enable signaling of processes (term, kill, oom-
              kill)
                      128 - allow reboot/poweroff
                      256 - allow nicing of all real-time tasks

              This file is present only if the CONFIG_MAGIC_SYSRQ kernel
              configuration option is enabled.  For further details see the
              Linux kernel source file Documentation/sysrq.txt.

       /proc/sys/kernel/version
              This file contains a string like:

                  #5 Wed Feb 25 21:49:24 MET 1998

              The "#5" means that this is the fifth kernel built from this
              source base and the date behind it indicates the time the
              kernel was built.

       /proc/sys/kernel/threads-max (since Linux 2.3.11)
              This file specifies the system-wide limit on the number of
              threads (tasks) that can be created on the system.

       /proc/sys/kernel/zero-paged (PowerPC only)
              This file contains a flag.  When enabled (nonzero), Linux-PPC
              will pre-zero pages in the idle loop, possibly speeding up
              get_free_pages.

       /proc/sys/net
              This directory contains networking stuff.  Explanations for
              some of the files under this directory can be found in tcp(7)
              and ip(7).

       /proc/sys/net/core/somaxconn
              This file defines a ceiling value for the backlog argument of
              listen(2); see the listen(2) manual page for details.

       /proc/sys/proc
              This directory may be empty.

       /proc/sys/sunrpc
              This directory supports Sun remote procedure call for network
              filesystem (NFS).  On some systems, it is not present.

       /proc/sys/vm
              This directory contains files for memory management tuning,
              buffer and cache management.

       /proc/sys/vm/drop_caches (since Linux 2.6.16)
              Writing to this file causes the kernel to drop clean caches,
              dentries, and inodes from memory, causing that memory to
              become free.  This can be useful for memory management testing
              and performing reproducible filesystem benchmarks.  Because
              writing to this file causes the benefits of caching to be
              lost, it can degrade overall system performance.

              To free pagecache, use:

                  echo 1 > /proc/sys/vm/drop_caches

              To free dentries and inodes, use:

                  echo 2 > /proc/sys/vm/drop_caches

              To free pagecache, dentries and inodes, use:

                  echo 3 > /proc/sys/vm/drop_caches

              Because writing to this file is a nondestructive operation and
              dirty objects are not freeable, the user should run sync(8)
              first.

       /proc/sys/vm/legacy_va_layout (since Linux 2.6.9)
              If nonzero, this disables the new 32-bit memory-mapping
              layout; the kernel will use the legacy (2.4) layout for all
              processes.

       /proc/sys/vm/memory_failure_early_kill (since Linux 2.6.32)
              Control how to kill processes when an uncorrected memory error
              (typically a 2-bit error in a memory module) that cannot be
              handled by the kernel is detected in the background by
              hardware.  In some cases (like the page still having a valid
              copy on disk), the kernel will handle the failure
              transparently without affecting any applications.  But if
              there is no other up-to-date copy of the data, it will kill
              processes to prevent any data corruptions from propagating.

              The file has one of the following values:

              1:  Kill all processes that have the corrupted-and-not-
                  reloadable page mapped as soon as the corruption is
                  detected.  Note this is not supported for a few types of
                  pages, like kernel internally allocated data or the swap
                  cache, but works for the majority of user pages.

              0:  Only unmap the corrupted page from all processes and kill
                  only a process that tries to access it.

              The kill is performed using a SIGBUS signal with si_code set
              to BUS_MCEERR_AO.  Processes can handle this if they want to;
              see sigaction(2) for more details.

              This feature is active only on architectures/platforms with
              advanced machine check handling and depends on the hardware
              capabilities.

              Applications can override the memory_failure_early_kill
              setting individually with the prctl(2) PR_MCE_KILL operation.

              Only present if the kernel was configured with
              CONFIG_MEMORY_FAILURE.

       /proc/sys/vm/memory_failure_recovery (since Linux 2.6.32)
              Enable memory failure recovery (when supported by the
              platform)

              1:  Attempt recovery.

              0:  Always panic on a memory failure.

              Only present if the kernel was configured with
              CONFIG_MEMORY_FAILURE.

       /proc/sys/vm/oom_dump_tasks (since Linux 2.6.25)
              Enables a system-wide task dump (excluding kernel threads) to
              be produced when the kernel performs an OOM-killing.  The dump
              includes the following information for each task (thread,
              process): thread ID, real user ID, thread group ID (process
              ID), virtual memory size, resident set size, the CPU that the
              task is scheduled on, oom_adj score (see the description of
              /proc/[pid]/oom_adj), and command name.  This is helpful to
              determine why the OOM-killer was invoked and to identify the
              rogue task that caused it.

              If this contains the value zero, this information is
              suppressed.  On very large systems with thousands of tasks, it
              may not be feasible to dump the memory state information for
              each one.  Such systems should not be forced to incur a
              performance penalty in OOM situations when the information may
              not be desired.

              If this is set to nonzero, this information is shown whenever
              the OOM-killer actually kills a memory-hogging task.

              The default value is 0.

       /proc/sys/vm/oom_kill_allocating_task (since Linux 2.6.24)
              This enables or disables killing the OOM-triggering task in
              out-of-memory situations.

              If this is set to zero, the OOM-killer will scan through the
              entire tasklist and select a task based on heuristics to kill.
              This normally selects a rogue memory-hogging task that frees
              up a large amount of memory when killed.

              If this is set to nonzero, the OOM-killer simply kills the
              task that triggered the out-of-memory condition.  This avoids
              a possibly expensive tasklist scan.

              If /proc/sys/vm/panic_on_oom is nonzero, it takes precedence
              over whatever value is used in
              /proc/sys/vm/oom_kill_allocating_task.

              The default value is 0.

       /proc/sys/vm/overcommit_memory
              This file contains the kernel virtual memory accounting mode.
              Values are:

                     0: heuristic overcommit (this is the default)
                     1: always overcommit, never check
                     2: always check, never overcommit

              In mode 0, calls of mmap(2) with MAP_NORESERVE are not
              checked, and the default check is very weak, leading to the
              risk of getting a process "OOM-killed".  Under Linux 2.4, any
              nonzero value implies mode 1.  In mode 2 (available since
              Linux 2.6), the total virtual address space on the system is
              limited to (SS + RAM*(r/100)), where SS is the size of the
              swap space, and RAM is the size of the physical memory, and r
              is the contents of the file /proc/sys/vm/overcommit_ratio.

       /proc/sys/vm/overcommit_ratio
              See the description of /proc/sys/vm/overcommit_memory.

       /proc/sys/vm/panic_on_oom (since Linux 2.6.18)
              This enables or disables a kernel panic in an out-of-memory
              situation.

              If this file is set to the value 0, the kernel's OOM-killer
              will kill some rogue process.  Usually, the OOM-killer is able
              to kill a rogue process and the system will survive.

              If this file is set to the value 1, then the kernel normally
              panics when out-of-memory happens.  However, if a process
              limits allocations to certain nodes using memory policies
              (mbind(2) MPOL_BIND) or cpusets (cpuset(7)) and those nodes
              reach memory exhaustion status, one process may be killed by
              the OOM-killer.  No panic occurs in this case: because other
              nodes' memory may be free, this means the system as a whole
              may not have reached an out-of-memory situation yet.

              If this file is set to the value 2, the kernel always panics
              when an out-of-memory condition occurs.

              The default value is 0.  1 and 2 are for failover of
              clustering.  Select either according to your policy of
              failover.

       /proc/sys/vm/swappiness
              The value in this file controls how aggressively the kernel
              will swap memory pages.  Higher values increase
              aggressiveness, lower values decrease aggressiveness.  The
              default value is 60.

       /proc/sysrq-trigger (since Linux 2.4.21)
              Writing a character to this file triggers the same SysRq
              function as typing ALT-SysRq-<character> (see the description
              of /proc/sys/kernel/sysrq).  This file is normally writable
              only by root.  For further details see the Linux kernel source
              file Documentation/sysrq.txt.

       /proc/sysvipc
              Subdirectory containing the pseudo-files msg, sem and shm.
              These files list the System V Interprocess Communication (IPC)
              objects (respectively: message queues, semaphores, and shared
              memory) that currently exist on the system, providing similar
              information to that available via ipcs(1).  These files have
              headers and are formatted (one IPC object per line) for easy
              understanding.  svipc(7) provides further background on the
              information shown by these files.

       /proc/timer_list (since Linux 2.6.21)
              This read-only file exposes a list of all currently pending
              (high-resolution) timers, all clock-event sources, and their
              parameters in a human-readable form.

       /proc/timer_stats (since Linux 2.6.21)
              This is a debugging facility to make timer (ab)use in a Linux
              system visible to kernel and user-space developers.  It can be
              used by kernel and user-space developers to verify that their
              code does not make undue use of timers.  The goal is to avoid
              unnecessary wakeups, thereby optimizing power consumption.

              If enabled in the kernel (CONFIG_TIMER_STATS), but not used,
              it has almost zero runtime overhead and a relatively small
              data-structure overhead.  Even if collection is enabled at
              runtime, overhead is low: all the locking is per-CPU and
              lookup is hashed.

              The /proc/timer_stats file is used both to control sampling
              facility and to read out the sampled information.

              timer_stats collects information about the timer events which
              are fired in a Linux system over a sample period:

              - the pid of the task(process) which initialized the timer -
              the name of the process which initialized the timer - the
              function where the timer was initialized - the callback
              function which is associated to the timer - the number of
              events (callbacks)

              The timer_stats functionality is inactive on bootup.  A
              sampling period can be started using the following command:

                  # echo 1 > /proc/timer_stats

              The following command stops a sampling period:

                  # echo 0 > /proc/timer_stats

              The statistics can be retrieved by:

                  $ cat /proc/timer_stats

              While sampling is enabled, each readout from /proc/timer_stats
              will see newly updated statistics.  Once sampling is disabled,
              the sampled information is kept until a new sample period is
              started.  This allows multiple readouts.

              Sample output from /proc/timer_stats:

   $ cat /proc/timer_stats
   Timer Stats Version: v0.3
   Sample period: 1.764 s
   Collection: active
     255,     0 swapper/3        hrtimer_start_range_ns (tick_sched_timer)
      71,     0 swapper/1        hrtimer_start_range_ns (tick_sched_timer)
      58,     0 swapper/0        hrtimer_start_range_ns (tick_sched_timer)
       4,  1694 gnome-shell      mod_delayed_work_on (delayed_work_timer_fn)
      17,     7 rcu_sched        rcu_gp_kthread (process_timeout)
   ...
       1,  4911 kworker/u16:0    mod_delayed_work_on (delayed_work_timer_fn)
      1D,  2522 kworker/0:0      queue_delayed_work_on (delayed_work_timer_fn)
   1029 total events, 583.333 events/sec

              The output columns are:

              *  a count of the number of events, optionally (since Linux
                 2.6.23) followed by the letter 'D' if this is a deferrable
                 timer;

              *  the PID of the process that initialized the timer;

              *  the name of the process that initialized the timer;

              *  the function where the timer was initialized; and

              *  (in parentheses) the callback function that is associated
                 with the timer.

       /proc/tty
              Subdirectory containing the pseudo-files and subdirectories
              for tty drivers and line disciplines.

       /proc/uptime
              This file contains two numbers: the uptime of the system
              (seconds), and the amount of time spent in idle process
              (seconds).

       /proc/version
              This string identifies the kernel version that is currently
              running.  It includes the contents of /proc/sys/kernel/ostype,
              /proc/sys/kernel/osrelease and /proc/sys/kernel/version.  For
              example:
            Linux version 1.0.9 (quinlan@phaze) #1 Sat May 14 01:51:54 EDT 1994

       /proc/vmstat (since Linux 2.6)
              This file displays various virtual memory statistics.

       /proc/zoneinfo (since Linux 2.6.13)
              This file display information about memory zones.  This is
              useful for analyzing virtual memory behavior.

NOTES         top

       Many strings (i.e., the environment and command line) are in the
       internal format, with subfields terminated by null bytes ('\0'), so
       you may find that things are more readable if you use od -c or tr
       "\000" "\n" to read them.  Alternatively, echo `cat <file>` works
       well.

       This manual page is incomplete, possibly inaccurate, and is the kind
       of thing that needs to be updated very often.

SEE ALSO         top

       cat(1), dmesg(1), find(1), free(1), ps(1), tr(1), uptime(1),
       chroot(2), mmap(2), readlink(2), syslog(2), slabinfo(5), hier(7),
       time(7), arp(8), hdparm(8), ifconfig(8), init(8), lsmod(8), lspci(8),
       mount(8), netstat(8), procinfo(8), route(8), sysctl(8)

       The Linux kernel source files: Documentation/filesystems/proc.txt
       Documentation/sysctl/fs.txt, Documentation/sysctl/kernel.txt,
       Documentation/sysctl/net.txt, and Documentation/sysctl/vm.txt.

COLOPHON         top

       This page is part of release 3.70 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       http://www.kernel.org/doc/man-pages/.

Linux                            2014-07-08                          PROC(5)