Hop on over to the fex project page and download the new version.

Changelist:

20071026 - First major release
  - Added some tests
  - If you want to specify a different first split token, the first character 
    can be any non-digit character which is not '-' or '{'.

    These are now equivalent:
    % echo "foo/bar/baz" | fex 0/2
    bar
    % echo "foo/bar/baz" | fex /2
    bar

    Previously, this would give an error due to a design decision.