How to create behavior like the $HOME variable I have grown to use the $HOME variable a lot.  So if I type $HOME/ and hit TAB it will write out /Users/user/.  If I do a partial $HOME/Down and hit TAB it will write out /Users/user/Downlaods.  I love this.  But if I go into my .bash_profile and create a var like TOR='/media/torrents', then do source /Users/user/.bash_profile and try hitting TAB after typing $TOR it does not do this behaviour.
Can someone help me understand why?
update:
playing around it does work on MAC creating a variable with path TOR='/media/torrents', on the command line doing $TOR/(notice the backslash) and hitting TAB it autopopulates.  This behaviour does not work on linux, centos in particular.
You need to set a shell option for this
shopt -s direxpand

either directly on the command line or in your startup files.
From man bash
direxpand
   If set, bash replaces directory names with  the  results
   of  word  expansion when performing filename completion.
   This  changes  the  contents  of  the  readline  editing
   buffer.   If not set, bash attempts to preserve what the
   user typed.