man/run0: Describe environment variables set (systemd#32622)

* man/run0: Describe environment variables set

man/run0.xml

@@ -219,6 +219,43 @@
     non-zero return value will be returned.</para>
   </refsect1>
 
+  <refsect1>
+    <title>Environment Variables</title>
+
+    <para>As with <command>systemd-run</command>, the session will inherit the system
+    environment from the service manager. In addition, the following environment variables will be set:</para>
+
+    <variablelist>
+      <varlistentry>
+        <term><varname>$TERM</varname></term>
+        <listitem><para>Copied from the <varname>$TERM</varname> of the caller. Can be overriden with <option>--setenv=</option></para>
+
+        <xi:include href="version-info.xml" xpointer="v256"/></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>$SUDO_USER</varname></term>
+        <listitem><para>Set to the username of the originating user.</para>
+
+        <xi:include href="version-info.xml" xpointer="v256"/></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>$SUDO_UID</varname></term>
+        <listitem><para>Set to the numeric UNIX user id of the originating user.</para>
+
+        <xi:include href="version-info.xml" xpointer="v256"/></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>$SUDO_GID</varname></term>
+        <listitem><para>Set to the primary numeric UNIX group id of the originating session.</para>
+
+        <xi:include href="version-info.xml" xpointer="v256"/></listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
   <refsect1>
     <title>See Also</title>
     <para><simplelist type="inline">