Not Writing a Builder: The Command Builder

Creating a Builder and attaching it to a construction environment allows for a lot of flexibility when you want to re-use actions to build multiple files of the same type. This can, however, be cumbersome if you only need to execute one specific command to build a single file (or group of files). For these situations, SCons supports a Command Builder that arranges for a specific action to be executed to build a specific file or files. This looks a lot like the other builders (like Program, Object, etc.), but takes as an additional argument the command to be executed to build the file:

     env = Environment()
     env.Command('foo.out', 'foo.in', "sed 's/x/y/' < $TARGET > $SOURCE")
  

    % scons .
    sed 's/x/y' < foo.in > foo.out
  

This is often more convenient than creating a Builder object and adding it to the BUILDERS variable of a construction environment

Note that the action you

     env = Environment()
     def build(target, source, env)
         XXX
         return None
     env.Command('foo.out', 'foo.in', build)
  

    % scons .
    build("foo.out", "foo.in")