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 structures 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 identi-
       fier 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 spec-
       ifies  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 spec-
       ified either by key or by identifier. (See below.)  Both keys and iden-
       tifiers may be specified in decimal,  hexadecimal  (specified  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 performed.

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

       -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	create
	      these  resources	at  start up and may not have any code to deal
	      unexpected disappearance.

       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 implementa-
       tions  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)