describe how to use cdist-env in every shell

Signed-off-by: Nico Schottelius <nico@kr.ethz.ch>

doc/man/cdist-env.text

@@ -16,9 +16,23 @@ cdist-env
 DESCRIPTION
 -----------
 cdist-env outputs two strings suitable for usage in your current shell,
-so you can use cdist from the checkout. You can evaluate those strings
-and make directory usage of them.
+so you can use cdist from the checkout. cdist-env essentially helps you
+to easily setup PATH and MANPATH.
 
+If you've multiple checkouts of cdist and run cdist-env from the various
+checkouts, a new run will prepend the last directory, thus ensures you
+can run it multiple times and does what one expects.
+
+EXAMPLES
+--------
+For use in bourne shell variants (like dash, bash, ksh) as well as
+in csh variants (csh, tcsh):
+
+--------------------------------------------------------------------------------
+eval `~/cdist/bin/cdist-env`
+--------------------------------------------------------------------------------
+
+Replace ~/cdist with the checkout directory of cdist.
 
 
 SEE ALSO