sys-utils/ipcs.1

   1 .\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
   2 .\" May be distributed under the GNU General Public License
   3 .TH IPCS "1" "July 2014" "util-linux" "User Commands"
   4 .SH NAME
   5 ipcs \- show information on IPC facilities
   6 .SH SYNOPSIS
   7 .B ipcs
   8 [options]
   9 .SH DESCRIPTION
  10 .B ipcs
  11 shows information on inter-process communication facilities.
  12 By default it shows information about all three resources:
  13 shared memory segments, message queues, and semaphore arrays.
  14 .SH OPTIONS
  15 .TP
  16 \fB\-i\fR, \fB\-\-id\fR \fIid\fR
  17 Show full details on just the one resource element identified by
  18 .IR id .
  19 This option needs to be combined with one of the three resource options:
  20 .BR \-m ,
  21 .BR \-q " or"
  22 .BR \-s .
  23 .TP
  24 \fB\-h\fR, \fB\-\-help\fR
  25 Display help text and exit.
  26 .TP
  27 \fB\-V\fR, \fB\-\-version\fR
  28 Display version information and exit.
  29 .SS "Resource options"
  30 .TP
  31 \fB\-m\fR, \fB\-\-shmems\fR
  32 Write information about active shared memory segments.
  33 .TP
  34 \fB\-q\fR, \fB\-\-queues\fR
  35 Write information about active message queues.
  36 .TP
  37 \fB\-s\fR, \fB\-\-semaphores\fR
  38 Write information about active semaphore sets.
  39 .TP
  40 \fB\-a\fR, \fB\-\-all\fR
  41 Write information about all three resources (default).
  42 .SS "Output formats"
  43 Of these options only one takes effect: the last one specified.
  44 .TP
  45 \fB\-c\fR, \fB\-\-creator\fR
  46 Show creator and owner.
  47 .TP
  48 \fB\-l\fR, \fB\-\-limits\fR
  49 Show resource limits.
  50 .TP
  51 \fB\-p\fR, \fB\-\-pid\fR
  52 Show PIDs of creator and last operator.
  53 .TP
  54 \fB\-t\fR, \fB\-\-time\fR
  55 Write time information.  The time of the last control operation that changed
  56 the access permissions for all facilities, the time of the last
  57 .BR msgsnd (2)
  58 and
  59 .BR msgrcv (2)
  60 operations on message queues, the time of the last
  61 .BR shmat (2)
  62 and
  63 .BR shmdt (2)
  64 operations on shared memory, and the time of the last
  65 .BR semop (2)
  66 operation on semaphores.
  67 .TP
  68 \fB\-u\fR, \fB\-\-summary\fR
  69 Show status summary.
  70 .SS "Representation"
  71 These affect only the \fB\-l\fR (\fB\-\-limits\fR) option.
  72 .TP
  73 \fB\-b\fR, \fB\-\-bytes\fR
  74 Print sizes in bytes.
  75 .TP
  76 .B \-\-human
  77 Print sizes in human-readable format.
  78 .SH CONFORMING TO
  79 The Linux ipcs utility is not fully compatible to the POSIX ipcs utility.
  80 The Linux version does not support the POSIX
  81 .BR \-a ,
  82 .B \-b
  83 and
  84 .B \-o
  85 options, but does support the
  86 .B \-l
  87 and
  88 .B \-u
  89 options not defined by POSIX.  A portable application shall not use the
  90 .BR \-a ,
  91 .BR \-b ,
  92 .BR \-o ,
  93 .BR \-l ,
  94 and
  95 .B \-u
  96 options.
  97 .SH NOTES
  98 The current implementation of
  99 .B ipcs
 100 obtains information about available IPC resources by parsing the files in
 101 .IR /proc/sysvipc .
 102 Before util-linux version v2.23, an alternate mechanism was used: the
 103 .BR IPC_STAT
 104 command of
 105 .BR msgctl (2),
 106 .BR semctl (2),
 107 and
 108 .BR shmctl (2).
 109 This mechanism is also used in later util-linux versions in the case where
 110 .I /proc
 111 is unavailable.
 112 A limitation of the
 113 .B IPC_STAT
 114 mechanism is that it can only be used to retrieve information about
 115 IPC resources for which the user has read permission.
 116 .SH AUTHORS
 117 .UR balasub@cis.ohio-state.edu
 118 Krishna Balasubramanian
 119 .UE
 120 .SH SEE ALSO
 121 .BR ipcmk (1),
 122 .BR ipcrm (1),
 123 .BR msgrcv (2),
 124 .BR msgsnd (2),
 125 .BR semget (2),
 126 .BR semop (2),
 127 .BR shmat (2),
 128 .BR shmdt (2),
 129 .BR shmget (2),
 130 .BR sysvipc (7)
 131 .SH AVAILABILITY
 132 The ipcs command is part of the util-linux package and is available from
 133 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
 134 Linux Kernel Archive
 135 .UE .