Document /etc/initrd-release

When systemd is started, it detects initrd by checking for that file
The usage of that file is not documented anywhere, so mention it early
in the most relevant man-page I could find.

diff --git a/man/bootup.xml b/man/bootup.xml
index 9468a613196994d2b3da41119a93013cda5b4950..d3715234000365fa89efd252c9e3f94c1dd7894b 100644 (file)
--- a/man/bootup.xml
+++ b/man/bootup.xml
@@ -156,7 +156,9 @@
     using systemd as well. In this case, boot up inside the initrd
     follows the following structure.</para>
 
-    <para>The default target in the initrd is
+    <para>systemd detects that it is run within an initrd by checking
+    for the file <filename>/etc/initrd-release</filename>.
+    The default target in the initrd is
     <filename>initrd.target</filename>. The bootup process begins
     identical to the system manager bootup (see above) until it
     reaches <filename>basic.target</filename>. From there, systemd