Usage:

  Once this is set up, environment variables will automatically
  reverse-resolve in your prompt.  Running fix_path with no arguments
  will either give you the current directory or an expression
  containing enviroment variables that when evaluated gives you the
  current directory

License:

  GPL v2 or later.  See the included file COPYING.

Installation:

  $ gcc -o fix_path fix_path.c
  $ cp fix_path somewhere_on_your_path/

  Then open your .bashrc and add:

  PS1="\u@\h \$(fix_path) $ "

  Reload bash.  Then to test this do something like:
    user@host ~ $ cd /tmp
    user@host /tmp $ export A="/tmp"
    user@host $A $
  
  If this is not the result you get, with $A substituted for /tmp in
  the last line, then something is wrong.  If you are pretty sure this
  is my fault, email me: cbr at sccs dot swarthmore dot edu

Known Issues:

  Some ways of configuring systems make getcwd() give annoying answers
  for home directories.  For example, on one system I use, my homedir
  looks like /home/jeff normally, but getcwd() yields
  /local/home/jeff.  This is a unix limitation.  Plan 9 fixes this,
  but has not been widely adopted.  The solution here is to hack the
  fix_home function to ignore some number of characters under certain
  circumstances.  I'd change:

    int fix_home(char* in_path)
    {
      if (starts_with(in_path, "/d4m/home/"))
        return sizeof("/d4m") - 1;
      if (starts_with(in_path, "/nfs/emc5/home/"))
        return sizeof("/nfs/emc5") - 1;
      return 0;
    }

  to:

    int fix_home(char* in_path)
    {
      if (starts_with(in_path, "/d4m/home/"))
         return sizeof("/d4m") - 1;
      if (starts_with(in_path, "/nfs/emc5/home/"))
         return sizeof("/nfs/emc5") - 1;
      if (starts_with(in_path, "/local/home/"))
         return sizeof("/local/home") -1;
      return 0;
    }

   to deal with the problem that /home/jeff is actually /local/home/jeff