filter_atom.py
A script to keep only atoms of certain type(s).
$ filter_atom.py -h
usage: filter_atom.py [-h] -a ATOM [input_file] [output_file]
positional arguments:
input_file by default, reads from stdin
output_file by default, writes to stdout
optional arguments:
-h, --help show this help message and exit
-a ATOM, --atom ATOM could be used multiple times (to keep more than one
atom)