Uservars

User vars differ from target arguments in that uservars cannot be modified after initiation of execution; a simple substitution rule is used.

% remember to 'quote' 
DIRECTORY = 'MyDir'

% use make-like syntax for uservar substitution.
all
  req: tgz($(DIRECTORY))       
          

Uservars can be overridden on the command line, like this:

skam all DIRECTORY=MyDir2