man: document snapshot units

Makefile.am

@@ -325,6 +325,7 @@ MANPAGES = \
 	man/systemd.path.5 \
 	man/systemd.target.5 \
 	man/systemd.device.5 \
+	man/systemd.snapshot.5 \
 	man/daemon.7 \
 	man/sd-daemon.7 \
 	man/runlevel.8 \

man/systemd.snapshot.xml

@@ -0,0 +1,87 @@
+<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+        "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<!--
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+-->
+
+<refentry id="systemd.snapshot">
+        <refentryinfo>
+                <title>systemd.snapshot</title>
+                <productname>systemd</productname>
+
+                <authorgroup>
+                        <author>
+                                <contrib>Developer</contrib>
+                                <firstname>Lennart</firstname>
+                                <surname>Poettering</surname>
+                                <email>lennart@poettering.net</email>
+                        </author>
+                </authorgroup>
+        </refentryinfo>
+
+        <refmeta>
+                <refentrytitle>systemd.snapshot</refentrytitle>
+                <manvolnum>5</manvolnum>
+        </refmeta>
+
+        <refnamediv>
+                <refname>systemd.snapshot</refname>
+                <refpurpose>systemd snapshot units</refpurpose>
+        </refnamediv>
+
+        <refsynopsisdiv>
+                <para><filename>systemd.snapshot</filename></para>
+        </refsynopsisdiv>
+
+        <refsect1>
+                <title>Description</title>
+
+                <para>Snapshot units are not configured via unit
+                configuration files. Nonetheless they are named
+                similar to filenames. A unit name whose name ends in
+                <filename>.snapshot</filename> refers to a dynamic
+                snapshot of the systemd runtime state.</para>
+
+                <para>Snapshots are not configured on disk but created
+                dynamically via <command>systemctl snapshot</command>
+                (see
+                <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                for details) or an equivalent command. When created
+                they will automatically get dependencies on the
+                currently activated units. They hence act as saved
+                runtime state of the systemd manager. Later on the
+                user may choose to return to the saved state via
+                <command>systemctl isolate</command>. They are hence
+                useful to roll back to a defined state after
+                temporarily starting/stopping services or
+                similar.</para>
+        </refsect1>
+
+        <refsect1>
+                  <title>See Also</title>
+                  <para>
+                          <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+                  </para>
+        </refsect1>
+
+</refentry>

man/systemd.unit.xml

@@ -151,10 +151,13 @@
                 with the device node <filename>/dev/sda</filename> in
                 the file system namespace. If this applies a special
                 way to escape the path name is used, so that it is
-                usable as part of a file name. Basically, given a path,
+                usable as part of a file name. Basically, given a
-                "/" is replaced by "-", and all unprintable characters
+                path, "/" is replaced by "-", and all unprintable
-                and the "-" are replaced by C-style "\x20"
+                characters and the "-" are replaced by C-style "\x20"
-                escapes. This escaping is reversible.</para>
+                escapes. The root directory "/" is encoded as single
+                dash, while otherwise the initial and ending "/" is
+                removed from all paths during transformation. This
+                escaping is reversible.</para>
 
                 <para>Optionally, units may be instantiated from a
                 template file at runtime. This allows creation of