A-Z or <literal>_</literal> (i.e. numbers and <literal>-</literal> are not permitted as first character). The
user/group name must have at least one character, and at most 31.</para>
+ <para>For further details about the syntax of user/group names, see <ulink
+ url="https://systemd.io/USER_NAMES">User/Group Name Syntax</ulink>.</para>
+
<para>It is strongly recommended to pick user and group names that are unlikely to clash with normal users
created by the administrator. A good scheme to guarantee this is by prefixing all system and group names with the
underscore, and avoiding too generic names.</para>
<refsect1>
<title>Specifiers</title>
- <para>Specifiers can be used in the "Name", "ID", "GECOS", "Home directory", and "Shell" fields.
- An unknown or unresolvable specifier is treated as invalid configuration.
- The following expansions are understood:</para>
- <table>
- <title>Specifiers available</title>
- <tgroup cols='3' align='left' colsep='1' rowsep='1'>
- <colspec colname="spec" />
- <colspec colname="mean" />
- <colspec colname="detail" />
- <thead>
- <row>
- <entry>Specifier</entry>
- <entry>Meaning</entry>
- <entry>Details</entry>
- </row>
- </thead>
- <tbody>
- <row>
- <entry><literal>%b</literal></entry>
- <entry>Boot ID</entry>
- <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
- </row>
- <row>
- <entry><literal>%H</literal></entry>
- <entry>Host name</entry>
- <entry>The hostname of the running system.</entry>
- </row>
- <row>
- <entry><literal>%m</literal></entry>
- <entry>Machine ID</entry>
- <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
- </row>
- <row>
- <entry><literal>%T</literal></entry>
- <entry>Directory for temporary files</entry>
- <entry>This is either <filename>/tmp</filename> or the path <literal>$TMPDIR</literal>, <literal>$TEMP</literal> or <literal>$TMP</literal> are set to.</entry>
- </row>
- <row>
- <entry><literal>%v</literal></entry>
- <entry>Kernel release</entry>
- <entry>Identical to <command>uname -r</command> output.</entry>
- </row>
- <row>
- <entry><literal>%V</literal></entry>
- <entry>Directory for larger and persistent temporary files</entry>
- <entry>This is either <filename>/var/tmp</filename> or the path <literal>$TMPDIR</literal>, <literal>$TEMP</literal> or <literal>$TMP</literal> are set to.</entry>
- </row>
- <row>
- <entry><literal>%%</literal></entry>
- <entry>Escaped <literal>%</literal></entry>
- <entry>Single percent sign.</entry>
- </row>
- </tbody>
- </tgroup>
- </table>
+ <para>Specifiers can be used in the <literal>Name</literal>, <literal>ID</literal>,
+ <literal>GECOS</literal>, <literal>Home directory</literal>, and <literal>Shell</literal> fields. An
+ unknown or unresolvable specifier is treated as invalid configuration. The following expansions are
+ understood:</para>
+
+ <table class='specifiers'>
+ <title>Specifiers available</title>
+ <tgroup cols='3' align='left' colsep='1' rowsep='1'>
+ <colspec colname="spec" />
+ <colspec colname="mean" />
+ <colspec colname="detail" />
+ <thead>
+ <row>
+ <entry>Specifier</entry>
+ <entry>Meaning</entry>
+ <entry>Details</entry>
+ </row>
+ </thead>
+ <tbody>
+ <xi:include href="standard-specifiers.xml" xpointer="a"/>
+ <xi:include href="standard-specifiers.xml" xpointer="b"/>
+ <xi:include href="standard-specifiers.xml" xpointer="B"/>
+ <xi:include href="standard-specifiers.xml" xpointer="H"/>
+ <xi:include href="standard-specifiers.xml" xpointer="l"/>
+ <xi:include href="standard-specifiers.xml" xpointer="m"/>
+ <xi:include href="standard-specifiers.xml" xpointer="o"/>
+ <row>
+ <entry><literal>%T</literal></entry>
+ <entry>Directory for temporary files</entry>
+ <entry>This is either <filename>/tmp</filename> or the path <literal>$TMPDIR</literal>, <literal>$TEMP</literal> or <literal>$TMP</literal> are set to.</entry>
+ </row>
+ <xi:include href="standard-specifiers.xml" xpointer="v"/>
+ <row>
+ <entry><literal>%V</literal></entry>
+ <entry>Directory for larger and persistent temporary files</entry>
+ <entry>This is either <filename>/var/tmp</filename> or the path <literal>$TMPDIR</literal>, <literal>$TEMP</literal> or <literal>$TMP</literal> are set to.</entry>
+ </row>
+ <xi:include href="standard-specifiers.xml" xpointer="w"/>
+ <xi:include href="standard-specifiers.xml" xpointer="W"/>
+ <xi:include href="standard-specifiers.xml" xpointer="percent"/>
+ </tbody>
+ </tgroup>
+ </table>
</refsect1>
<refsect1>