Selkie command line

Invoked as:

$ python -m selkie COM ARG ...

One can generally substitute - for a filename to mean stdin/stdout.

The commands are:

• get — Extract a range of lines from a file. Arguments: filename, start line number (counting from 0), end line number (counting from 0).

• ud — Unicode dump. Prints each line of the file, followed by one line for each character, giving the hex code and description of the Unicode character.