Batch Renaming Files in Mac OS X

So, iPhoto screwed up my library AGAIN (I reeeeaaallly wish Google would make a Picasa for Mac), and I was getting sick of having to look at every one of my several thousand photos and put it in the right folder, along with classifying them as originals, exports for upload, or edits. I decided that renaming the picture files was the only way I could save myself this trouble the next time this happened. Long story short, I was about to give up on my search for a free renamer for Mac and shell out 20 bucks for payware (I shudder at the thought) when, in an act of desperation, I scanned the comments on all the Lifehacker posts about renaming files in bulk (which pertained, annoyingly enough, only to Windows).

Luckily, one commenter had mentioned the free app NameChanger for Mac OS X. I just about cried when I used it for the first time, that's how awesome it is. The program allows you to drag-and-drop files to rename onto the icon or into the program, and shows you a live preview of what the filenames will look like after you're finished.

Later, while playing with Automator (which comes with Tiger) for my Desktop Cleaner program, I discovered that Automator can rename photos. By selecting "Show Action When Run," it's possible to specify what to replace and what to replace it WITH. However, NameChanger has several advantages.

1. No programming required. Just download and extract, and it's ready to go.
2. As-you-type preview. A little gimmicky, but cool.
3. Ability to replace first, last, or all occurrences of a term.

But the Automator option has some things going for it too, such as the ability to put a date before or after a name (NameChanger can only put it after); the ability to use date created, modified, or current date; and different customizability of dates. But for me, it's much nicer to just download a program that does the work for you.