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 inter-process 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 im-
mediate (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 ob-
jects of all three types in a single command line, with objects speci-
fied either by key or by identifier (see below). Both keys and identi-
fiers may be specified in decimal, hexadecimal (specified with an ini-
tial '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 performed 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 performed.
-m, --shmem-id shmid
Remove the shared memory segment identified by shmid after the
last detach is performed.
-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 re-
spect the same command-line syntax. For backward compatibility the
previous syntax is still supported.
SEE ALSO
ipcmk(1), ipcs(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 <https://www.kernel.org/pub/linux/utils/util-
linux/>.
util-linux July 2014 IPCRM(1)