ipcs -- provide information on ipc facilities


ipcs [-smq] [-tcp]


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

Note: Although this command has many similarities with the optional ipcs utility described in POSIX 1003.1-2008 (ISO/IEC 9945-2009), it has substantial differences and is therefore described separately. The options specified here have similar meaning to those in POSIX 1003.1-2008 (ISO/IEC 9945-2009); other options specified there have unspecified behavior on an LSB conforming implementation. See Application Usage below. The output format is not specified.

Resource display options


shared memory segments.


message queues.


semaphore arrays.

Output format options







Application Usage

In some implementations of ipcs the -a option will print all information available. In other implementations the -a option will print all resource types. Therefore, applications shall not use the -a option.

Some implementations of ipcs provide more output formats than are specified here. These options are not consistent between differing implementations of ipcs. Therefore, only the -t, -c and -p option formatting flags may be used. At least one of the -t, -c and -p options and at least one of -m, -q and -s options shall be specified. If no options are specified, the output is unspecified.