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
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.
-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.
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 ALSOipcs(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)