doc: os-release: mention all shell characters that must be escaped

Since the manpage already talks about shell-compatibility, it should be
more accurate about what needs to be escaped and how.

diff --git a/man/os-release.xml b/man/os-release.xml
index b2983049432bbb29f2fcac14f0b433ceb192b9f3..b4cbeba39558f6f6ca86776a85ff8e061a87a600 100644 (file)
--- a/man/os-release.xml
+++ b/man/os-release.xml
@@ -68,17 +68,16 @@
                 (this means variable expansion is explicitly not
                 supported), allowing applications to read the file
                 without implementing a shell compatible execution
-                engine. Variable assignment values should be enclosed
-                in double or single quotes if they include spaces,
+                engine. Variable assignment values must be enclosed in
+                double or single quotes if they include spaces,
                 semicolons or other special characters outside of A-Z,
-                a-z, 0-9. All strings should be in UTF-8 format, and
-                non-printable characters should not be used. If double
-                or single quotes or backslashes are to be used within
-                variable assignments, they should be escaped with
-                backslashes, following shell style. It is not
-                supported to concatenate multiple individually quoted
-                strings. Lines beginning with "#" shall be ignored as
-                comments.</para>
+                a-z, 0-9.  Shell special characters ("$", quotes,
+                backslash, backtick) must be escaped with backslashes,
+                following shell style.  All strings should be in UTF-8
+                format, and non-printable characters should not be used.
+                It is not supported to concatenate multiple individually
+                quoted strings. Lines beginning with "#" shall be
+                ignored as comments.</para>
 
                 <para>The file <filename>/etc/os-release</filename>
                 takes precedence over