ipcs — show information on IPC facilities
ipcs [options]
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.
−i, −−id idShow 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, −−helpDisplay help text and exit.
−V, −−versionDisplay version information and exit.
−m, −−shmemsWrite information about active shared memory segments.
−q, −−queuesWrite information about active message queues.
−s, −−semaphoresWrite information about active semaphore sets.
−a, −−allWrite information about all three resources (default).
Of these options only one takes effect: the last one specified.
−c, −−creatorShow creator and owner.
−l, −−limitsShow resource limits.
−p, −−pidShow PIDs of creator and last operator.
−t, −−timeWrite 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, −−summaryShow status summary.
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.
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.
ipcmk(1), ipcrm(1), msgrcv(2), msgsnd(2), semget(2), semop(2), shmat(2), shmdt(2), shmget(2), sysvipc(7)
The ipcs command is part of the util-linux package and is available from Linux Kernel Archive
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Copyright 1993 Rickard E. Faith (faithcs.unc.edu) May be distributed under the GNU General Public License |