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 NOTES
  79 The current implementation of
  80 .B ipcs
  81 obtains information about available IPC resources by parsing the files in
  82 .IR /proc/sysvipc .
  83 Before util-linux version v2.23, an alternate mechanism was used: the
  84 .BR IPC_STAT
  85 command of
  86 .BR msgctl (2),
  87 .BR semctl (2),
  88 and
  89 .BR shmctl (2).
  90 This mechanism is also used in later util-linux versions in the case where
  91 .I /proc
  92 is unavailable.
  93 A limitation of the
  94 .B IPC_STAT
  95 mechanism is that it can only be used to retrieve information about
  96 IPC resources for which the user has read permission.
  97 .SH CONFORMING TO
  98 The Linux ipcs utility is not fully compatible to the POSIX ipcs utility.
  99 The Linux version does not support the POSIX
 100 .BR \-a ,
 101 .B \-b
 102 and
 103 .B \-o
 104 options, but does support the
 105 .B \-l
 106 and
 107 .B \-u
 108 options not defined by POSIX.  A portable application shall not use the
 109 .BR \-a ,
 110 .BR \-b ,
 111 .BR \-o ,
 112 .BR \-l ,
 113 and
 114 .B \-u
 115 options.
 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 .SH AVAILABILITY
 131 The ipcs command is part of the util-linux package and is available from
 132 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
 133 Linux Kernel Archive
 134 .UE .