parallel.docbook

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   2
   3 <!--
   4
   5 Written by Joey Hess
   6
   7 -->
   8
   9 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.4//EN"
  10 "file:///usr/share/xml/docbook/schema/dtd/4.4/docbookx.dtd"
  11 []>
  12
  13 <refentry>
  14         <refentryinfo>
  15                 <address>
  16                         <email>joey@kitenet.net</email>
  17                 </address>
  18                 <author>
  19                         <firstname>Joey</firstname>
  20                         <surname>Hess</surname>
  21                 </author>
  22                 <date>2009-07-02</date>
  23         </refentryinfo>
  24
  25         <refmeta>
  26                 <refentrytitle>parallel</refentrytitle>
  27                 <manvolnum>1</manvolnum>
  28         </refmeta>
  29
  30         <refnamediv>
  31                 <refname>parallel</refname>
  32                 <refpurpose>run programs in parallel</refpurpose>
  33         </refnamediv>
  34
  35         <refsynopsisdiv>
  36                 <cmdsynopsis>
  37                         <command>parallel</command>
  38                         <arg>options</arg>
  39                         <arg>command</arg>
  40                         <command>--</command>
  41                         <arg>argument ...</arg>
  42                 </cmdsynopsis>
  43                 <cmdsynopsis>
  44                         <command>parallel</command>
  45                         <arg>options</arg>
  46                         <command>--</command>
  47                         <arg>command ...</arg>
  48                 </cmdsynopsis>
  49         </refsynopsisdiv>
  50
  51         <refsect1>
  52                 <title>DESCRIPTION</title>
  53
  54                 <para><command>parallel</command> runs the specified command,
  55                 passing it a single one of the specified arguments. This is
  56                 repeated for each argument. Jobs may be run in
  57                 parallel. The default is to run one job per CPU.</para>
  58
  59                 <para>If no command is specified before the --,
  60                 the commands after it are instead run in parallel.</para>
  61
  62         </refsect1>
  63
  64         <refsect1>
  65                 <title>OPTIONS</title>
  66
  67                 <variablelist>
  68
  69                 <varlistentry>
  70                         <term><option>-j maxjobs</option></term>
  71                         <listitem>
  72                                 <para>Use to limit the number of jobs
  73                                 that are run at the same time.</para>
  74                         </listitem>
  75                 </varlistentry>
  76
  77                 <varlistentry>
  78                         <term><option>-l maxload</option></term>
  79                         <listitem>
  80                                 <para>Wait as needed to avoid starting
  81                                 new jobs when the system's load average
  82                                 is not below the specified limit.</para>
  83                         </listitem>
  84                 </varlistentry>
  85
  86                 <varlistentry>
  87                         <term><option>-i</option></term>
  88                         <listitem>
  89                                 <para>Normally the command is passed the
  90                                 argument at the end of its command line. With
  91                                 this option, any instances of "{}" in
  92                                 the command are replaced with the argument.</para>
  93                         </listitem>
  94                 </varlistentry>
  95
  96                 <varlistentry>
  97                         <term><option>-n</option></term>
  98                         <listitem>
  99                                 <para>Number of arguments to pass to a
 100                                 command at a time. Default is 1.
 101                                 Incompatible with -i</para>
 102                         </listitem>
 103                 </varlistentry>
 104
 105                 </variablelist>
 106
 107         </refsect1>
 108
 109         <refsect1>
 110                 <title>EXAMPLE</title>
 111
 112         <para>
 113         <cmdsynopsis>
 114                 <command>parallel sh -c "echo hi; sleep 2; echo bye" -- 1 2 3</command>
 115         </cmdsynopsis>
 116         </para>
 117
 118         <para>This runs three subshells that each print a message, delay,
 119                 and print another message. If your system has multiple
 120                 CPUs, parallel will run some of the jobs in parallel,
 121                 which should be clear from the order the messages are
 122                 output.
 123         </para>
 124
 125         <para>
 126         <cmdsynopsis>
 127                 <command>parallel -j 3 ufraw -o processed -- *.NEF</command>
 128         </cmdsynopsis>
 129         </para>
 130
 131         <para>This runs three ufraw processes at the same time until
 132         all of the NEF files have been processed.
 133         </para>
 134
 135         <para>
 136         <cmdsynopsis>
 137                 <command>parallel -j 3 -- ls df "echo hi"</command>
 138         </cmdsynopsis>
 139         </para>
 140
 141         <para>This runs three independent commands in parallel.</para>
 142
 143         </refsect1>
 144
 145         <refsect1>
 146                 <title>EXIT STATUS</title>
 147
 148
 149         <para>Its exit status is the combination of the exit statuses of each
 150         command ran, ORed together. (Thus, if any one command
 151         exits nonzero, <command>parallel</command> as a whole will exit nonzero.)</para>
 152
 153         </refsect1>
 154
 155         <refsect1>
 156                 <title>AUTHOR</title>
 157                 <para>
 158                         Tollef Fog Heen
 159                 </para>
 160         </refsect1>
 161
 162 </refentry>