Add && to Appendix C

source/C/command_line.rst

@@ -59,3 +59,9 @@ If you want just to see the contents of a file on standard output run
    cat [filename]
 
 If you have a command and you don't want to type the whole thing out you can press the :kbd:`tab` key. If this does not work press :kbd:`tab` again and see the list of avaialable commands to run.
+
+If you want a command to run if the first completes run 
+
+.. code::
+
+   command 1 && command 2