There are different philosophies where to put "external" executables.
 * FreeBSD puts them in /usr/local/bin, but
 * NetBSD puts them in /usr/pkg/bin, and
 * others place them in /opt or even more exotic places.
 
The official recommendation to use "#! /usr/bin/env ..." leads to semi-
functional scripts.

From *BSD ports/pkgsrc, we need lang/python27 and shells/bash.

To my knowledge, there is nothing in my scripts that requires python27 over
python2x (with x<7), but, to my astonishment, *BSD won't install any
executable named "python2" or "python", so that the path needs to contain
the revision number.
