ipcs - show information on IPC facilities
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 id
Of these options only one takes effect: the last one specified.
These affect only the -l (--limits) option.
By default, the unit, sizes are expressed in, is byte, and unit prefixes are in power of 2^10 (1024). Abbreviations of symbols are exhibited truncated in order to reach a better readability, by exhibiting alone the first letter of them; examples: "1 KiB" and "1 MiB" are respectively exhibited as "1 K" and "1 M", then omitting on purpose the mention "iB", which is part of these abbreviations.
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.
Krishna Balasubramanian <firstname.lastname@example.org>
ipcmk(1), ipcrm(1), msgrcv(2), msgsnd(2), semget(2), semop(2), shmat(2), shmdt(2), shmget(2), sysvipc(7)
For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.
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/.