This is merely my personal note. I was about to rename all my files under a directory. I need to replace the space with underscore character ('_'). My first thought was a simple bash script to do that. Apparently, it’s been very long time since my last bash coding session. I spent 15 minutes reading how to read all files and rename them. And I got nothing.
Luckily, I know python. Stupid me. Why didn’t I think it at first time. It was couple minutes of python and all the spaces were replaced by underscores. Thanks to python. All I did were
$ python
Python 2.5.2 (r252:60911, Oct 5 2008, 19:24:49)
[GCC 4.3.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> files = os.listdir('./')
>>> for f in files:
... os.rename(f, f.replace(' ', '_'))
...
>>>
Or if you want to save in a script, you could you this
#!/usr/bin/python
import os
import sys
files = os.listdir(sys.argv[1])
for f in files:
os.rename(f, f.replace(' ', '_'))
The script takes the directory path as the argument. You could modify the script to use regex to have a better rename rule 
