Man1 - ipcs.1
Table of Contents
NAME
ipcs - show information on IPC facilities
SYNOPSIS
ipcs [options]
DESCRIPTION
ipcs shows information on System V inter-process communication facilities. By default it shows information about all three resources: shared memory segments, message queues, and semaphore arrays.
OPTIONS
-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.
Representation
These affect only the -l (–limits) option.
-b, –bytes
Print sizes in bytes.
–human
Print sizes in human-readable format.
CONFORMING TO
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 options.
NOTES
The current implementation of ipcs obtains information about available IPC resources by parsing the files in /proc/sysvipc. Before util-linux version v2.23, an alternate mechanism was used: the IPC_STAT command of msgctl*(2), *semctl*(2), and *shmctl*(2). This mechanism is also used in later util-linux versions in the case where /proc is unavailable. A limitation of the *IPC_STAT mechanism is that it can only be used to retrieve information about IPC resources for which the user has read permission.
AUTHORS
SEE ALSO
*ipcmk*(1), *ipcrm*(1), *msgrcv*(2), *msgsnd*(2), *semget*(2), *semop*(2), *shmat*(2), *shmdt*(2), *shmget*(2), *sysvipc*(7)
REPORTING BUGS
For bug reports, use the issue tracker at https://github.com/karelzak/util-linux/issues.
AVAILABILITY
The ipcs command is part of the util-linux package which can be downloaded from Linux Kernel Archive https://www.kernel.org/pub/linux/utils/util-linux/.