Linux/Unux ipcs command

NAME
       ipcs - provide information on ipc facilities

SYNOPSIS
       ipcs [ -asmq ] [ -tclup ]
       ipcs [ -smq ] -i id
       ipcs -h

DESCRIPTION
       ipcs provides information on the ipc facilities for which the calling process has read access.

       The -i option allows a specific resource id to be specified.  Only information on this id will be printed.

       Resources may be specified as follows:

       -m     shared memory segments

       -q     message queues

       -s     semaphore arrays

       -a     all (this is the default)

       The output format may be specified as follows:

       -t     time

       -p     pid

       -c     creator

       -l     limits

       -u     summary
[root@netus221 ~]# ipcs

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status
0x74007313 393216     root      600        4          0

------ Semaphore Arrays --------
key        semid      owner      perms      nsems
0xa100f6c2 163840     root      666        2

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages
0x0100f741 0          root       0          0            0

[root@netus221 ~]# ipcs -u

------ Shared Memory Status --------
segments allocated 1
pages allocated 1
pages resident  1
pages swapped   0
Swap performance: 0 attempts     0 successes

------ Semaphore Status --------
used arrays = 1
allocated semaphores = 2

------ Messages: Status --------
allocated queues = 1
used headers = 0
used space = 0 bytes

[root@netus221 ~]# ipcs -h
ipcs provides information on ipc facilities for which you have read access.
Resource Specification:
        -m : shared_mem
        -q : messages
        -s : semaphores
        -a : all (default)
Output Format:
        -t : time
        -p : pid
        -c : creator
        -l : limits
        -u : summary
-i id [-s -q -m] : details on resource identified by id
usage : ipcs -asmq -tclup
        ipcs [-s -m -q] -i id
        ipcs -h for help.
[root@netus221 ~]#