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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | EXAMPLES | EXIT STATUS | NOTES | BUGS | SEE ALSO | REPORTING BUGS | COLOPHON |
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PGREP(1) General Commands Manual PGREP(1)
pgrep, pkill, pidwait - look up, signal, or wait for processes
based on name and other attributes
pgrep [option ...] pattern
pkill [option ...] pattern
pidwait [option ...] pattern
pgrep looks through the currently running processes and lists the
process IDs which match the selection criteria to stdout. All the
criteria have to match. For example,
$ pgrep -u root sshd
will only list the processes whose name include sshd AND owned by
root. On the other hand,
$ pgrep -u root,daemon
will list the processes owned by root OR daemon.
pkill will send the specified signal (by default SIGTERM) to each
process instead of listing them on stdout.
pidwait will wait for each process instead of listing them on
stdout.
-signal
--signal signal
Defines the signal to send to each matched process. Either
the numeric or the symbolic signal name can be used. In
pgrep or pidwait mode only the long option can be used and
has no effect unless used in conjunction with
--require-handler to filter to processes with a userspace
signal handler present for a particular signal.
-a, --list-full
List the full command line as well as the process ID.
(pgrep only.)
-A, --ignore-ancestors
Ignore all ancestors of pgrep, pkill, or pidwait. For
example, this can be useful when elevating with sudo or
similar tools.
-c, --count
Suppress normal output; instead print a count of matching
processes. When count does not match anything, e.g.
returns zero, the command will return non-zero value. Note
that for pkill and pidwait, the count is the number of
matching processes, not the processes that were
successfully signaled or waited for.
-d, --delimiter delimiter
Sets the string used to delimit each process ID in the
output (by default a newline). (pgrep only.)
-e, --echo
Display name and PID of the process being killed. (pkill
only.)
-f, --full
The pattern is normally only matched against the process
name. When -f is set, the full command line is used.
-F, --pidfile file
Read PIDs from file. This option is more useful for pkill
or pidwait than pgrep. The filename "-" can be used to
read from STDIN. Conflicts with the --pid option.
-g, --pgroup pgrp,...
Only match processes in the process group IDs listed.
Process group 0 is translated into pgrep's, pkill's, or
pidwait's own process group.
-G, --group gid,...
Only match processes whose real group ID is listed. Either
the numerical or symbolical value may be used.
-H, --require-handler
Only match processes with a userspace signal handler
present for the signal to be sent.
-i, --ignore-case
Match processes case-insensitively.
-l, --list-name
List the process name as well as the process ID. (pgrep
only.)
-L, --logpidfile
Fail if pidfile (see -F) not locked.
-m, --mrelease
After sending the signal, invoke the process_mrelease()
system call to immediately free the target process's
memory.
-n, --newest
Select only the newest (most recently started) of the
matching processes.
-o, --oldest
Select only the oldest (least recently started) of the
matching processes.
-O, --older secs
Select processes older than secs.
-p, --pid pid,...
Only match processes whose process ID is listed. Conflicts
with the --pidfile option.
-P, --parent ppid,...
Only match processes whose parent process ID is listed.
-q, --queue value
Send the integer value along with the signal. This option
will either use pidfd_send_signal(2) with a value applied
or sigqueue(3) rather than kill(2). If the receiving
process has installed a handler for this signal using the
SA_SIGINFO flag to sigaction(2), then it can obtain this
data via the si_value field of the siginfo_t structure.
-Q, --shell-quote
Output the command line in shell-quoted form. (pgrep
only.)
-r, --runstates D,R,S,Z,...
Match only processes which match the process state.
-s, --session sid,...
Only match processes whose process session ID is listed.
Session ID 0 is translated into pgrep's, pkill's, or
pidwait's own session ID.
-t, --terminal term,...
Only match processes whose controlling terminal is listed.
The terminal name should be specified without the "/dev/"
prefix.
-u, --euid euid,...
Only match processes whose effective user ID is listed.
Either the numerical or symbolical value may be used.
-U, --uid uid,...
Only match processes whose real user ID is listed. Either
the numerical or symbolical value may be used.
-v, --inverse
Negates the matching. This option is usually used in
pgrep's or pidwait's context. In pkill's context the short
option is disabled to avoid accidental usage of the option.
-w, --lightweight
Shows all thread ids instead of pids in pgrep's or
pidwait's context. In pkill's context this option is
disabled.
-x, --exact
Only match processes whose names (or command lines if -f is
specified) exactly match the pattern.
--cgroup name,...
Match on provided control group (cgroup) v2 name. See
cgroups(7)
--env name[=value],...
Match on process that have these environment variables. If
the =value parameter is not defined then only the variable
name is matched.
--ns pid
Match processes that belong to the same namespaces.
Required to run as root to match processes from other
users. See --nslist for how to limit which namespaces to
match.
--nslist name,...
Match only the provided namespaces. Available namespaces:
ipc, mnt, net, pid, user, uts.
-V, --version
Display version information and exit.
-h, --help
Display help and exit.
pattern
Specifies an Extended Regular Expression for matching
against the process names or command lines.
Example 1: Find the process ID of the named daemon:
$ pgrep -u root named
Example 2: Make syslog reread its configuration file:
$ pkill -HUP syslogd
Example 3: Give detailed information on all bash processes:
$ ps -fp $(pgrep -d, -x bash)
Example 4: Make all chrome processes run nicer:
$ renice +4 $(pgrep chrome)
Example 5: Wait for a process with a known PID to finish:
$ echo ${PID} | pidwait -F -
0 One or more processes matched the criteria. For pkill and
pidwait, one or more processes must also have been
successfully signalled or waited for.
1 No processes matched or none of them could be signalled.
2 Syntax error in the command line.
3 Fatal error: out of memory etc.
The process name used for matching is limited to the 15 characters
present in the output of /proc/pid/stat. Use the -f option to
match against the complete command line, /proc/pid/cmdline.
Threads may not have the same process name as the parent process
but will have the same command line.
The running pgrep, pkill, or pidwait process will never report
itself as a match.
The -O --older option will silently fail if /proc is mounted with
the subset=pid option.
pkill will attempt to use pidfd_send_signal(2) instead of kill(2)
or sigqueue(3) to send a signal to the target process if it is
able to get the process file descriptor.
The options -n and -o and -v can not be combined. Let me know if
you need to do this.
If processes start in the same clock tick (usually but not always
a 100th of a second), the options -n and -o will not be able to
distinguish which process started in the same clock tick and may
give erroneous results.
Defunct processes are reported.
pidwait requires the pidfd_open(2) system call which first
appeared in Linux 5.3.
killall(1), kill(1), ps(1), skill(1), kill(2), sigaction(2),
pidfd_open(2), pidfd_send_signal(2), sigqueue(3), cgroups(7),
regex(7), signal(7)
Please send bug reports to ⟨procps@freelists.org⟩.
This page is part of the procps-ng (/proc filesystem utilities)
project. Information about the project can be found at
⟨https://gitlab.com/procps-ng/procps⟩. If you have a bug report
for this manual page, see
⟨https://gitlab.com/procps-ng/procps/blob/master/Documentation/bugs.md⟩.
This page was obtained from the project's upstream Git repository
⟨https://gitlab.com/procps-ng/procps.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-07-30.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
procps-ng 2025-06-11 PGREP(1)
Pages that refer to this page: fuser(1), kill(1@@procps-ng), killall(1), pidof(1), pmap(1), ps(1), pslog(1), pwdx(1), skill(1)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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