lckdo.docbook

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   2
   3 <!--
   4
   5 Written by Michael Tokarev <mjt@tls.msk.ru>
   6 Public domain.
   7
   8 -->
   9
  10 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.4//EN"
  11 "file:///usr/share/xml/docbook/schema/dtd/4.4/docbookx.dtd"
  12 []>
  13
  14 <refentry>
  15         <refentryinfo>
  16                 <address>
  17                         <email>mjt@tls.msk.ru</email>
  18                 </address>
  19                 <author>
  20                         <firstname>Michael</firstname>
  21                         <surname>Tokarev</surname>
  22                 </author>
  23                 <date>2007-08-15</date>
  24         </refentryinfo>
  25
  26         <refmeta>
  27                 <refentrytitle>lckdo</refentrytitle>
  28                 <manvolnum>1</manvolnum>
  29         </refmeta>
  30
  31         <refnamediv>
  32                 <refname>lckdo</refname>
  33                 <refpurpose>run a program with a lock held</refpurpose>
  34         </refnamediv>
  35
  36         <refsynopsisdiv>
  37                 <cmdsynopsis>
  38                         <command>lckdo</command>
  39                         <arg>options</arg>
  40                         <arg choice="req">lockfile</arg>
  41                         <arg choice="req">program</arg>
  42                         <arg>arguments</arg>
  43                 </cmdsynopsis>
  44         </refsynopsisdiv>
  45
  46         <refsect1>
  47                 <title>DESCRIPTION</title>
  48
  49                 <para><command>lckdo</command> runs a program with a lock
  50                 held, in order to prevent multiple processes from running in
  51                 parallel. Use just like <command>nice</command> or
  52                 <command>nohup</command>.</para>
  53
  54         </refsect1>
  55
  56         <refsect1>
  57                 <title>OPTIONS</title>
  58
  59                 <variablelist>
  60
  61                 <varlistentry>
  62                         <term><option>-w</option></term>
  63                         <listitem>
  64                                 <para>If the lock is already held by another process,
  65                                 wait for it to complete instead of failing
  66                                 immediately.</para>
  67                         </listitem>
  68                 </varlistentry>
  69
  70                 <varlistentry>
  71                         <term><option>-W {sec}</option></term>
  72                         <listitem>
  73                                 <para>The same as -w but wait not more than sec
  74                                 seconds.</para>
  75                         </listitem>
  76                 </varlistentry>
  77
  78                 <varlistentry>
  79                         <term><option>-e</option></term>
  80                         <listitem>
  81                                 <para>Execute the program directly without forking and
  82                                 waiting (keeps an extra file descriptor open).</para>
  83                         </listitem>
  84                 </varlistentry>
  85
  86                 <varlistentry>
  87                         <term><option>-E {nnn}</option></term>
  88                         <listitem>
  89                                 <para>Set the file descriptor number to keep open when
  90                                 exec()ing (implies -e).</para>
  91                         </listitem>
  92                 </varlistentry>
  93
  94                 <varlistentry>
  95                         <term><option>-n</option></term>
  96                         <listitem>
  97                                 <para>Do not create the lock file if it does not
  98                                 exist.</para>
  99                         </listitem>
 100                 </varlistentry>
 101
 102                 <varlistentry>
 103                         <term><option>-q</option></term>
 104                         <listitem>
 105                                 <para>Produce no output if lock is already held.</para>
 106                         </listitem>
 107                 </varlistentry>
 108
 109                 <varlistentry>
 110                         <term><option>-s</option></term>
 111                         <listitem>
 112                                 <para>Lock in shared (read) mode.</para>
 113                         </listitem>
 114                 </varlistentry>
 115
 116                 <varlistentry>
 117                         <term><option>-x</option></term>
 118                         <listitem>
 119                                 <para>Lock in exclusive (write) mode (default).</para>
 120                         </listitem>
 121                 </varlistentry>
 122
 123                 <varlistentry>
 124                         <term><option>-t</option></term>
 125                         <listitem>
 126                                 <para>Test for lock existence.</para>
 127                         </listitem>
 128                 </varlistentry>
 129
 130                 </variablelist>
 131
 132         </refsect1>
 133
 134         <refsect1>
 135                 <title>EXIT STATUS</title>
 136
 137         <para>If the lock was successfully acquired, the return value is that
 138         of the program invoked by <command>lckdo</command>. If the lock
 139         couldn't be acquired, EX_TEMPFAIL is returned. If there was a problem
 140         opening/creating or locking the lock file, EX_CANTCREAT or EX_OSERR
 141         will be returned.</para>
 142
 143         </refsect1>
 144
 145 </refentry>