man: document updated newline support

Since v239 newlines have been allowed for PassEnvironment=
and EnvironmentFile=, due to #8471.

This PR documents the behavior change.

diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 6dcccc38b4f49eb9b6ddedb5e1dac0761b0b9bd1..2f6fc0b5ba3c381381ff4f6483ef1613bb79ec59 100644 (file)
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -1869,6 +1869,12 @@ SystemCallErrorNumber=EPERM</programlisting>
         variable definitions. The parser strips leading and trailing whitespace from the values of assignments, unless
         you use double quotes (").</para>
 
+        <para><ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C escapes</ulink>
+        are supported, but not
+        <ulink url="https://en.wikipedia.org/wiki/Control_character#In_ASCII">most control characters</ulink>.
+        <literal>\t</literal> and <literal>\n</literal> can be used to insert tabs and newlines within
+        <varname>EnvironmentFile=</varname>.</para>
+
         <para>The argument passed should be an absolute filename or wildcard expression, optionally prefixed with
         <literal>-</literal>, which indicates that if the file does not exist, it will not be read and no error or
         warning message is logged. This option may be specified more than once in which case all specified files are
@@ -1899,6 +1905,12 @@ SystemCallErrorNumber=EPERM</programlisting>
         <para>Variables set for invoked processes due to this setting are subject to being overridden by those
         configured with <varname>Environment=</varname> or <varname>EnvironmentFile=</varname>.</para>
 
+        <para><ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C escapes</ulink>
+        are supported, but not
+        <ulink url="https://en.wikipedia.org/wiki/Control_character#In_ASCII">most control characters</ulink>.
+        <literal>\t</literal> and <literal>\n</literal> can be used to insert tabs and newlines within
+        <varname>EnvironmentFile=</varname>.</para>
+
         <para>Example:
         <programlisting>PassEnvironment=VAR1 VAR2 VAR3</programlisting>
         passes three variables <literal>VAR1</literal>,