man: systemd.exec - explicit Environment assignment

Hi all,

while working on another bug, I discovered the "strange" way systemd is
parsing Environment= in .service and thought it was worth documenting
(because I don't expect people to find this syntax by themselves unless
they read the parsing code ;)

Be more verbose about using space in Environment field and not
using value of other variables

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=840260

[zj: expand and reformat the example a bit]

diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 8a22ac013857da530f7ef35cb16c6de1ecfe3831..a0fca5996b16ad80f80bb107e7ed470e2828f336 100644 (file)
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -286,9 +286,24 @@
                                 empty string is assigned to this
                                 option the list of environment
                                 variables is reset, all prior
                                 empty string is assigned to this
                                 option the list of environment
                                 variables is reset, all prior

-                                assignments have no effect. See
+                                assignments have no effect.
+                                Variable expansion is not performed
+                                inside the strings, and $ has no special
+                                meaning.
+                                If you need to assign a value containing spaces
+                                to a variable, use double quotes (")
+                                for the assignment.</para>
+
+                                <para>Example:
+                                <programlisting>Environment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"</programlisting>
+                                gives three variables <literal>VAR1</literal>,
+                                <literal>VAR2</literal>, <literal>VAR3</literal>.
+                                </para>
+
+                                <para>
+                                See

                                 <citerefentry><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                                 <citerefentry><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>

-                                for details.</para></listitem>
+                                for details about environment variables.</para></listitem>

                         </varlistentry>
                         <varlistentry>
                                 <term><varname>EnvironmentFile=</varname></term>
                         </varlistentry>
                         <varlistentry>
                                 <term><varname>EnvironmentFile=</varname></term>