Use sed to change multiple filenames

I wanted to replace all hyphens in all filenames starting with 2003- and ending with .php. Here's how I did it using sed (no guarantees, no warranties, use at your own risk!):

1. Backup the files!
2. Change to the directory you want to make the changes in.
3. Then, to make sure the right filenames will be changed, list the filenames using the following sed command (modify "2003-*.php" and the sed search and replace strings for your situation):
   
   for filename in 2003-*.php; do echo $filename | sed \e 's/\-/\_/g'; done
   
   
4. When you're sure the above sed command is listing the right filenames, change it as follows (modify "2003-*.php" and the sed search and replace strings for your situation):
   
   for filename in 2003-*.php; do newname=`echo $filename | sed \e 's/\-/\_/g'`; mv $filename $newname; done

Note the use of the backtick character (`) (also known as backquote) which, on my keyboard, is located to the left of the "1" key. The backtick character is used in addition to the single quote character (').

[Update January 4, 2009] I totally forgot that I could have used the "rename" command instead of sed! There is control over which underscore in a filename is changed. More about renaming files using "rename".