man/systemd-vpick.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   5
   6 <refentry id="systemd-vpick"
   7     xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd-vpick</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd-vpick</refentrytitle>
  16     <manvolnum>1</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd-vpick</refname>
  21     <refpurpose>Resolve paths to <literal>.v/</literal> versioned directories</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <cmdsynopsis>
  26       <command>systemd-vpick <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">PATH</arg></command>
  27     </cmdsynopsis>
  28   </refsynopsisdiv>
  29
  30   <refsect1>
  31     <title>Description</title>
  32
  33     <para><command>systemd-vpick</command> resolves a file system path referencing a <literal>.v/</literal>
  34     versioned directory to a path to the newest (by version) file contained therein. This tool provides a
  35     command line interface for the
  36     <citerefentry><refentrytitle>systemd.v</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  37     logic.</para>
  38
  39     <para>The tool expects a path to a <literal>.v/</literal> directory as argument (either directly, or with
  40     a triple underscore pattern as final component). It then determines the newest file contained in that
  41     directory, and writes its path to standard output.</para>
  42
  43     <para>Unless the triple underscore pattern is passed as last component of the path, it is typically
  44     necessary to at least specify the <option>--suffix=</option> switch to configure the file suffix to look
  45     for.</para>
  46
  47     <para>If the specified path does not reference a <literal>.v/</literal> path (i.e. neither the final
  48     component ends in <literal>.v</literal>, nor the penultimate does or the final one does contain a triple
  49     underscore) it specified path is written unmodified to standard output.</para>
  50   </refsect1>
  51
  52   <refsect1>
  53     <title>Options</title>
  54
  55     <para>The following options are understood:</para>
  56
  57     <variablelist>
  58       <varlistentry>
  59         <term><option>--basename=</option></term>
  60         <term><option>-B</option></term>
  61
  62         <listitem><para>Overrides the "basename" of the files to look for, i.e. the part to the left of the
  63         variable part of the filenames. Normally this is derived automatically from the filename of the
  64         <literal>.v</literal> component of the specified path, or from the triple underscore pattern in the
  65         last component of the specified path.</para>
  66
  67         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
  68       </varlistentry>
  69
  70       <varlistentry>
  71         <term><option>-V</option></term>
  72
  73         <listitem><para>Explicitly configures the version to select. If specified, a filename with the
  74         specified version string will be looked for, instead of the newest version
  75         available.</para>
  76
  77         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
  78       </varlistentry>
  79
  80       <varlistentry>
  81         <term><option>-A</option></term>
  82
  83         <listitem><para>Explicitly configures the architecture to select. If specified, a filename with the
  84         specified architecture identifier will be looked for. If not specified only filenames with a locally
  85         supported architecture are considered, or those without any architecture identifier.</para>
  86
  87         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
  88       </varlistentry>
  89
  90       <varlistentry>
  91         <term><option>--suffix=</option></term>
  92         <term><option>-S</option></term>
  93
  94         <listitem><para>Configures the suffix of the filenames to consider. For the <literal>.v/</literal>
  95         logic it is necessary to specify the suffix to look for, and the <literal>.v/</literal> component
  96         must also carry the suffix immediately before <literal>.v</literal> in its name.</para>
  97
  98         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
  99       </varlistentry>
 100
 101       <varlistentry>
 102         <term><option>--type=</option></term>
 103         <term><option>-t</option></term>
 104
 105         <listitem><para>Configures the inode type to look for in the <literal>.v/</literal> directory. Takes
 106         one of <literal>reg</literal>, <literal>dir</literal>, <literal>sock</literal>,
 107         <literal>fifo</literal>, <literal>blk</literal>, <literal>chr</literal>, <literal>lnk</literal> as
 108         argument, each identifying an inode type. See <citerefentry
 109         project='man-pages'><refentrytitle>inode</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
 110         details about inode types. If this option is used inodes not matching the specified type are filtered
 111         and not taken into consideration.</para>
 112
 113         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
 114       </varlistentry>
 115
 116       <varlistentry>
 117         <term><option>--print=</option></term>
 118         <term><option>-p</option></term>
 119
 120         <listitem><para>Configures what precisely to write to standard output. If not specified prints the
 121         full, resolved path of the newest matching file in the <literal>.v/</literal> directory. This switch can be set to one of the following:</para>
 122
 123         <itemizedlist>
 124           <listitem><para>If set to <literal>filename</literal>, will print only the filename instead of the full path of the resolved file.</para></listitem>
 125           <listitem><para>If set to <literal>version</literal>, will print only the version of the resolved file.</para></listitem>
 126           <listitem><para>If set to <literal>type</literal>, will print only the inode type of the resolved
 127           file (i.e. a string such as <literal>reg</literal> for regular files, or <literal>dir</literal> for
 128           directories).</para></listitem>
 129           <listitem><para>If set to <literal>arch</literal>, will print only the architecture of the resolved
 130           file.</para></listitem>
 131           <listitem><para>If set to <literal>tries</literal>, will print only the tries left/tries done of the
 132           resolved file.</para></listitem>
 133           <listitem><para>If set to <literal>all</literal>, will print all of the above in a simple tabular
 134           output.</para></listitem>
 135         </itemizedlist>
 136
 137         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
 138       </varlistentry>
 139
 140       <varlistentry>
 141         <term><option>--resolve=</option></term>
 142
 143         <listitem><para>Takes a boolean argument. If true the path to the versioned file is fully
 144         canonicalized (i.e. symlinks resolved, and redundant path components removed) before it is shown. If
 145         false (the default) this is not done, and the path is shown without canonicalization.</para>
 146
 147         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
 148       </varlistentry>
 149
 150       <xi:include href="standard-options.xml" xpointer="help" />
 151       <xi:include href="standard-options.xml" xpointer="version" />
 152     </variablelist>
 153   </refsect1>
 154
 155   <refsect1>
 156     <title>Examples</title>
 157
 158     <para>Use a command like the following to automatically pick the newest raw disk image from a
 159     <literal>.v/</literal> directory:</para>
 160
 161     <programlisting>$ systemd-vpick --suffix=.raw --type=reg /var/lib/machines/quux.raw.v/</programlisting>
 162
 163     <para>This will enumerate all regular files matching
 164     <filename>/var/lib/machines/quux.raw.v/quux*.raw</filename>, filter and sort them according to the rules
 165     described in
 166     <citerefentry><refentrytitle>systemd.v</refentrytitle><manvolnum>7</manvolnum></citerefentry>, and then
 167     write the path to the newest (by version) file to standard output.</para>
 168
 169     <para>Use a command like the following to automatically pick the newest OS directory tree from a
 170     <literal>.v/</literal> directory:</para>
 171
 172     <programlisting>$ systemd-vpick --type=dir /var/lib/machines/waldo.v/</programlisting>
 173
 174     <para>This will enumerate all directory inodes matching
 175     <filename>/var/lib/machines/waldo.v/waldo*</filename>, filter and sort them according to the rules
 176     described in
 177     <citerefentry><refentrytitle>systemd.v</refentrytitle><manvolnum>7</manvolnum></citerefentry>, and then
 178     write the path to the newest (by version) directory to standard output.</para>
 179
 180     <para>For further examples see
 181     <citerefentry><refentrytitle>systemd.v</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
 182   </refsect1>
 183
 184   <refsect1>
 185     <title>Exit status</title>
 186
 187     <para>On success, 0 is returned, a non-zero failure code
 188     otherwise.</para>
 189   </refsect1>
 190
 191   <refsect1>
 192     <title>See Also</title>
 193     <para><simplelist type="inline">
 194       <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
 195       <member><citerefentry><refentrytitle>systemd.v</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
 196     </simplelist></para>
 197   </refsect1>
 198 </refentry>