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ipcs - Reports Interprocess Communication (IPC) facility status
ipcs [-a|-bcopt] [-mqs] [-C corefile] [-N namelist]
The
ipcs
command writes to the standard output information
about active Interprocess Communication (IPC) facilities.
Same as specifying the
-b,
-c,
-o,
-p, and
-t
options.
Writes the maximum number of bytes in message queues, the
size of segments for shared memory, and the number of semaphores in each semaphore
set.
Writes the username and group name of the user that made the
facility.
Writes report based on contents of file
corefile
instead of
/dev/kmem.
Writes information about active shared memory segments.
Writes report based on contents of file
namelist
instead of
/vmunix.
Writes the following usage information:
Number of messages on queue
Total number of bytes in message queues
Number of processes attached to shared memory segments
Writes the following:
Process number of the last process to receive a message on
message queues
Process number of the creating process
Process number of last process to attach or detach on shared
memory segments
Writes information about active message queues.
Writes information about active semaphore set.
Writes the following:
Time of the last control operation that changed the access
permissions for all facilities
Time of the last
msgsnd()
and last
msgrcv()
on message queues
Time of the last
shmat()
and last
shmdt()
on shared memory
Time of the last
semop()
on semaphore sets
If you
do not specify any options,
ipcs
writes information in
a short form about currently active message queues, shared memory segments,
semaphores, remote queues, and local queue headers.
The column headings and the meaning of the columns in an ipcs listing follow. The letters in parentheses indicate the flags that cause the corresponding heading to appear. The all means that the heading always appears. These flags only determine what information is provided for each facility. They do not determine which facilities are listed. Type of facility: Message queue Shared memory segment Semaphore The identifier for the facility entry. The key used as a parameter to the msgget(), semget() or shemget() system calls to make the facility entry.
Sample output from entering ipcs without options follows.
Message Queues:
T ID KEY MODE OWNER GROUP
q 4 0x41002ab4 --rw------- root system
Shared Memory:
T ID KEY MODE OWNER GROUP
m 0 0x3253bc5c --rw-rw-rw- root system
m 129 0 DLrw------- root daemon
Semaphores:
T ID KEY MODE OWNER GROUP
s 0 0x41002ab4 --ra------- root system
Output is formatted differently if the environment variable CMD_ENV is set to the string svr4. For example:
IPC status from /dev/kmem as of Thu Mar 26 11:31:03 1998
T ID KEY MODE OWNER GROUP
Message Queues:
q 4 0x41002ab4 --rw------- root system
Shared Memory:
m 0 0x3253bc5c --rw-rw-rw- root system
m 129 0 DLrw------- root daemon
Semaphores:
s 0 0x41002ab4 --ra------- root system
Contains user information.
Contains group information.
Commands: ipcrm(1)
Functions: msgrcv(2), msgsnd(2), semop(2), shmat(2), shmdt(2)