Quickly access directories from anywhere, with a shell function and Python script

mydirs.py

from __future__ import print_function

# The definitions are in the file "mydirs.dat" which is in the same directory
# as this file. Lines of this file may be blank or a label/directory pair,
# colon delimited. These can contain just about anything that doesn't confuse
# the shell, except colons and newlines, of course.

# Into your .bashrc, .profile, .zshrc, or whatever:
# cd_()
# {
#    cd `python /home/memyselfi/python/mydirs.py $@`
# }

import sys
import os.path as osp

DIRS = dict( [[i.strip() for i in ln.split(':')] \
   for ln in open(osp.join(osp.dirname(__file__),
   'mydirs.dat'), 'r') if ln.strip()] )

if len(sys.argv) < 2:
   print('Usage: cd_ [directory lookup key]', file=sys.stderr)
   tgt = '.'

else:
   tgt = DIRS.get(sys.argv[1], None)

   if not tgt:
      print('cd_: unrecognized key: "{0}"'.format(sys.argv[1]), file=sys.stderr)
      tgt = '.'

if tgt == '.':
   print('recognized keys:', ', '.join(DIRS.keys()), file=sys.stderr)

print(tgt)