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IPCRM(1)                                  User Commands                                  IPCRM(1)

NAME
       ipcrm - remove certain IPC resources

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 (specified
       with an initial '0x' or '0X'), or octal (specified with an initial '0').

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

OPTIONS
       -a, --all [shm] [msg] [sem]
              Remove  all  resources.   When  an option argument is provided, the removal is per‐
              formed only for the specified resource types.  Warning!  Do not use -a if  you  are
              unsure  how  the software using the resources might react to missing objects.  Some
              programs create these resources at startup and may not have any code to  deal  with
              an unexpected disappearance.

       -M, --shmem-key shmkey
              Remove  the shared memory segment created with shmkey after the last detach is per‐
              formed.

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

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

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

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

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

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.

NOTES
       In  its  first  Linux implementation, ipcrm used the deprecated syntax shown in the second
       line of 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 command-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                                  July 2014                                    IPCRM(1)

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