sw - swap filenames, for example to reorder numbered files
Usage: sw [FILENAMES A] [FILENAMES B]
For example:

  cat 1 2 3 4
Welcome
To
My
Lair
  sw 1 2 3 4  3 2 1 4
  cat 1 2 3 4
My
To
Welcome
Lair

All arguments are perceived to be filenames,
exceptions are --help and --version arguments.

To build just do "gcc sw.c -o sw".