For example, one of the other common tasks I perform on a regular basis is removing
all the bytecode files in a tree. Because these are not always portable across major Python
releases, it’s usually a good idea to ship programs without them and let Python create
new ones on first imports. Now that we’re expert os.walk users, we could cut out the
middleman and use it directly. Example 6-14 codes a portable and general command-
line tool, with support for arguments, exception processing, tracing, and list-only
mode.
Example 6-14. PP4E\Tools\cleanpyc.py
"""
delete all .pyc bytecode files in a directory tree: use the
command line arg as root if given, else current working dir
"""
import os, sys
findonly = False
rootdir = os.getcwd() if len(sys.argv) == 1 else sys.argv[1]
found = removed = 0
for (thisDirLevel, subsHere, filesHere) in os.walk(rootdir):
for filename in filesHere:
if filename.endswith('.pyc'):
fullname = os.path.join(thisDirLevel, filename)
print('=>', fullname)
if not findonly:
try:
os.remove(fullname)
removed += 1
except:
type, inst = sys.exc_info()[:2]
print(''4, 'Failed:', filename, type, inst)
found += 1
print('Found', found, 'files, removed', removed)
When run, this script walks a directory tree (the CWD by default, or else one passed
in on the command line), deleting any and all bytecode files along the way:
C:\...\Examples\PP4E> Tools\cleanpyc.py
=> C:\Users\mark\Stuff\Books\4E\PP4E\dev\Examples\PP4E\__init__.pyc
=> C:\Users\mark\Stuff\Books\4E\PP4E\dev\Examples\PP4E\Preview\initdata.pyc
=> C:\Users\mark\Stuff\Books\4E\PP4E\dev\Examples\PP4E\Preview\make_db_file.pyc
=> C:\Users\mark\Stuff\Books\4E\PP4E\dev\Examples\PP4E\Preview\manager.pyc
=> C:\Users\mark\Stuff\Books\4E\PP4E\dev\Examples\PP4E\Preview\person.pyc
...more lines here...
Found 24 files, removed 24C:\...\PP4E\Tools> cleanpyc.py.
=> .\find.pyc
=> .\visitor.pyc
=> .\__init__.pyc
Found 3 files, removed 3Searching Directory Trees | 325