IPCRM(1)                                  User Commands                                  IPCRM(1)



NAME
       ipcrm - remove a message queue, semaphore set or shared memory id

SYNOPSIS
       ipcrm [options]
       ipcrm {shm|msg|sem} id...

DESCRIPTION
       ipcrm removes System V interprocess communication (IPC) objects and associated data struc-
       tures from the system.  In order to delete such objects, you must  be  superuser,  or  the
       creator or owner of the object.

       System  V  IPC  objects are of three types: shared memory, message queues, and semaphores.
       Deletion of a message queue or semaphore object is immediate (regardless  of  whether  any
       process  still  holds  an  IPC identifier for the object).  A shared memory object is only
       removed after all currently attached processes have detached (shmdt(2))  the  object  from
       their virtual address space.

       Two syntax styles are supported.  The old Linux historical syntax specifies a three letter
       keyword indicating which class of object is to be deleted, followed by  one  or  more  IPC
       identifiers for objects of this type.

       The  SUS-compliant  syntax  allows  the specification of zero or more objects of all three
       types in a single command line, with objects specified either by  key  or  by  identifier.
       (See  below.)   Both keys and identifiers may be specified in decimal, hexadecimal (speci-
       fied with an initial '0x' or '0X'), or octal (specified with an initial '0').

OPTIONS
       -M, --shmem-key shmkey
              removes the shared memorysegment created with shmkey after the last detach is  per-
              formed.

       -m, --shmem-id shmid
              removes the shared memory segment identified by shmid after the last detach is per-
              formed.

       -Q, --queue-key msgkey
              removes the message queue created with msgkey.

       -q, --queue-id msgid
              removes the message queue identified by msgid.

       -S, --semaphore-key semkey
              removes the semaphore created with semkey.

       -s, --semaphore-id semid
              removes the semaphore identified by semid.

       -a, --all [shm msg sem]
              Remove all resources. When option argument is provided  the  removal  is  performed
              only  to for the specified resource types. Warning! Do not use -a if you are unsure
              how the software using resources might react on missing objects. Some programs cre-
              ate these resources at start up and may not have any code to deal unexpected disap-
              pearance.

       The details of the removes are described in  msgctl(2),  shmctl(2),  and  semctl(2).   The
       identifiers and keys may be found by using ipcs(1).

NOTES
       In its first Linux implementation, ipcrm used the deprecated syntax shown in the SYNOPSIS.
       Functionality present in other *nix implementations of ipcrm has since been added,  namely
       the ability to delete resources by key (not just identifier), and to respect the same com-
       mand-line syntax. For backward compatibility the previous syntax is still supported.

SEE ALSO
       ipcs(1),  ipcmk(1),  msgctl(2),  msgget(2),  semctl(2),  semget(2),  shmctl(2),  shmdt(2),
       shmget(2), ftok(3)

AVAILABILITY
       The  ipcrm  command  is  part of the util-linux package and is available from Linux Kernel
       Archive <ftp://ftp.kernel.org/pub/linux/utils/util-linux/>.



util-linux                                September 2011                                 IPCRM(1)