man: mention that systemd-sysusers understand the specifier.

diff --git a/man/sysusers.d.xml b/man/sysusers.d.xml
index 71f6926..534f008 100644 (file)
--- a/man/sysusers.d.xml
+++ b/man/sysusers.d.xml
@@ -230,6 +230,66 @@ u     root     0              "Superuser"           /root          /bin/zsh</pro
   </refsect1>
 
   <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>
+  </refsect1>
+
+  <refsect1>
     <title>Idempotence</title>
 
     <para>Note that <command>systemd-sysusers</command> will do nothing if the