Variable modifiers in csh and bash: csh

csh has a nice feature called variable modification to easily trim your variable for your needs. The modifiers work by appending to the variable interpolation with a ":". This feature is especially useful dealing with pathnames.

For example

% set gatesfile=/home/gates/bin/foo.bar
% echo $gatesfile
/home/gates/bin/foo.bar

In order to get the directory name, you only need this:

% echo $gatesfile:h
home/gates/bin

and for file name:

% echo $gatesfile:t
foo.bar

how about file base? Use combinations:

% echo $gatesfile:r:t
foo

Ok, here is all of the appendixes:

  +----------------------------------------------------------+
  |Modifier   Meaning               Example   Results        |
  +----------------------------------------------------------+
  |r          Root                  $a:r      a/b/c.d.e.f    |
  |e          Extension             $a:e      g              |
  |h          Head (or Directory)   $a:h      /a/b           |
  |t          Tail (or Filename)    $a:t      c.d.e.f.g      |
  +----------------------------------------------------------+