IPCS(1)                         User Commands                        IPCS(1)

NAME         top

       ipcs - show information on IPC facilities

SYNOPSIS         top

       ipcs [options]

DESCRIPTION         top

       ipcs shows information on the inter-process communication facilities
       for which the calling process has read access.  By default it shows
       information about all three resources: shared memory segments,
       message queues, and semaphore arrays.

OPTIONS         top

       -i, --id id
              Show full details on just the one resource element identified
              by id.  This option needs to be combined with one of the three
              resource options: -m, -q or -s.

       -h, --help
              Display help text and exit.

       -V, --version
              Display version information and exit.

   Resource options
       -m, --shmems
              Write information about active shared memory segments.

       -q, --queues
              Write information about active message queues.

       -s, --semaphores
              Write information about active semaphore sets.

       -a, --all
              Write information about all three resources (default).

   Output formats
       Of these options only one takes effect: the last one specified.

       -c, --creator
              Show creator and owner.

       -l, --limits
              Show resource limits.

       -p, --pid
              Show PIDs of creator and last operator.

       -t, --time
              Write time information.  The time of the last control
              operation that changed the access permissions for all
              facilities, the time of the last msgsnd(2) and msgrcv(2)
              operations on message queues, the time of the last shmat(2)
              and shmdt(2) operations on shared memory, and the time of the
              last semop(2) operation on semaphores.

       -u, --summary
              Show status summary.

       These affect only the -l (--limits) option.

       -b, --bytes
              Print sizes in bytes.

              Print sizes in human-readable format.

SEE ALSO         top

       ipcmk(1), ipcrm(1), msgrcv(2), msgsnd(2), semget(2), semop(2),
       shmat(2), shmdt(2), shmget(2)

CONFORMING TO         top

       The Linux ipcs utility is not fully compatible to the POSIX ipcs
       utility.  The Linux version does not support the POSIX -a, -b and -o
       options, but does support the -l and -u options not defined by POSIX.
       A portable application shall not use the -a, -b, -o, -l, and -u

AUTHOR         top

       Krishna Balasubramanian ⟨⟩

AVAILABILITY         top

       The ipcs command is part of the util-linux package and is available
       from Linux Kernel Archive 

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨⟩.  If you have a
       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on
       2020-02-08.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-02-05.)  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

util-linux                        July 2014                          IPCS(1)

Pages that refer to this page: ipcmk(1)ipcrm(1)msgctl(2)semctl(2)shmctl(2)proc(5)sysvipc(7)