ipcs(1) - f34

1IPCS(1)                          User Commands                         IPCS(1)
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NAME

6       ipcs - show information on IPC facilities
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SYNOPSIS

9       ipcs [options]
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DESCRIPTION

12       ipcs  shows information on System V inter-process communication facili‐
13       ties.  By default it  shows  information  about  all  three  resources:
14       shared memory segments, message queues, and semaphore arrays.
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OPTIONS

17       -i, --id id
18              Show full details on just the one resource element identified by
19              id.  This option needs to be combined  with  one  of  the  three
20              resource options: -m, -q or -s.
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22       -h, --help
23              Display help text and exit.
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25       -V, --version
26              Display version information and exit.
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28   Resource options
29       -m, --shmems
30              Write information about active shared memory segments.
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32       -q, --queues
33              Write information about active message queues.
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35       -s, --semaphores
36              Write information about active semaphore sets.
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38       -a, --all
39              Write information about all three resources (default).
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41   Output formats
42       Of these options only one takes effect: the last one specified.
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44       -c, --creator
45              Show creator and owner.
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47       -l, --limits
48              Show resource limits.
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50       -p, --pid
51              Show PIDs of creator and last operator.
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53       -t, --time
54              Write  time information.  The time of the last control operation
55              that changed the access permissions for all facilities, the time
56              of  the  last  msgsnd(2)  and  msgrcv(2)  operations  on message
57              queues, the time of the last shmat(2) and shmdt(2) operations on
58              shared  memory,  and  the time of the last semop(2) operation on
59              semaphores.
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61       -u, --summary
62              Show status summary.
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64   Representation
65       These affect only the -l (--limits) option.
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67       -b, --bytes
68              Print sizes in bytes.
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70       --human
71              Print sizes in human-readable format.
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CONFORMING TO

74       The Linux ipcs utility is not fully compatible to the POSIX ipcs  util‐
75       ity.   The  Linux  version  does  not  support  the POSIX -a, -b and -o
76       options, but does support the -l and -u options not defined  by  POSIX.
77       A  portable  application  shall  not  use  the  -a,  -b, -o, -l, and -u
78       options.
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NOTES

81       The current implementation of ipcs obtains information about  available
82       IPC resources by parsing the files in /proc/sysvipc.  Before util-linux
83       version v2.23, an alternate mechanism was used: the IPC_STAT command of
84       msgctl(2),  semctl(2),  and  shmctl(2).  This mechanism is also used in
85       later util-linux versions in the case where /proc  is  unavailable.   A
86       limitation  of  the  IPC_STAT  mechanism is that it can only be used to
87       retrieve information about IPC resources for which the  user  has  read
88       permission.
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AUTHORS

91       Krishna Balasubramanian ⟨balasub@cis.ohio-state.edu⟩
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AVAILABILITY

98       The ipcs command is part of the util-linux  package  and  is  available
99       from Linux Kernel Archive ⟨https://www.kernel.org/pub/linux/utils/util-
100       linux/⟩.
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104util-linux                         July 2014                           IPCS(1)