[Tutor] Script Feedback
damontimm at gmail.com
Tue Mar 30 16:27:43 CEST 2010
As a self-taught Python user I am still looking for insight on the
most pythonic and programmatically-friendly way of accomplishing a
given task. In this case, I have written a script that will perform a
“clean bzip2″ of a directory (or directories). Mac OS X (via AFP and
netatalk, in my case) tends leaves a bunch of ugly files/directories
hanging around and I would rather not include them in my compressed
In writing the script, though, I ran into some questions and I am not
sure what the recommended approach would be. The script works, as it
is, but I feel its a little hacked together and also a little limited
in its application. There is something to be said for programs that
"just work" (this does) but I want to take it a little further as an
educational endeavor and would like it to appear robust,
future-thinking, and pythonic.
My initial questions are:
1. Is there a better way to implement a --quiet flag?
2. I am not very clear on the use of Exceptions (or even if I am using
it in a good way here) — is what I have done the right approach?
3. Finally, in general: any feedback on how to improve this? (I am
thinking, just now, that the script is only suitable for a command
line usage, and couldn’t be imported by another script, for example.)
Any feedback is greatly appreciated. Writing a script like this is a
good learning tool (for me, at least).
I have posted this email online if you want to see the script with
pretty code formatting:
Thanks for any insight you may provide.
#! /usr/bin/env python
'''Script to perform a "clean" bzip2 on a directory (or directories). Removes
extraneous files that are created by Apple/AFP/netatalk before compressing.
from optparse import OptionParser
IGNORE_DIRS = ( '.AppleDouble', )
IGNORE_FILES = ('.DS_Store', )
'''If the destination tar.bz2 file already exists.'''
'''Ignore defined files and directories when doing the walk.'''
for dirpath, dirnames, filenames in os.walk(directory):
dirnames[:] = [ dn for dn in dirnames if dn not in IGNORE_DIRS ]
filenames[:] = [ fn for fn in filenames if fn not in IGNORE_FILES ]
yield dirpath, dirnames, filenames
for directory in directories:
file_name = '-'.join(directory.split(' '))
tar_name = file_name.replace('/','').lower() + ".tar.bz2"
if not options.quiet:
print 'Compressing files into: ' + tar_name
tar = tarfile.open(tar_name, 'w:bz2')
for dirpath, dirnames, filenames in ignore_walk(directory):
for file in filenames:
if not options.quiet:
print os.path.join(dirpath, file)
if __name__ == "__main__":
parser = OptionParser(usage="%prog [options: -q ] [directory]")
parser.add_option("-q", "--quiet", action="store_true", dest="quiet")
options, args = parser.parse_args()
directories = 
for arg in args:
print "Ingoring: %s (it's not a directory)." % arg
print "A tar file already exists this this directory name."
print "Move or rename it and try again."
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