What tools exist to rename (truncate) batches of files in OS X

Here are a few options to recover a file from user error of this type:

1. TimeMachine - your best hope.
2. Dropbox also keeps deleted files and versions if you stored that file in a folder that synced.
3. mdfind MYSCRIPT.py #better than locate and searches inside files, not just file names
4. Check your repositories if you use code control software like git or mercurial or svn or other tools
5. General undelete software like Data Rescue

As you're now aware, the terminal is unforgiving and doesn't have an "are you sure you meant to clobber that file?" design mentality. It gets worse when you realize recursive commands and the fact that everything is a file (directories, disks, disk images, etc...) and errant commands can delete vast amounts of work in the blink of an eye.

Try something like this:

 for file in Picture*.jpg
 do
    mv "$file" "vacation-$file"
 done  

(open terminal and add one line {press Enter} at a time.)

What that does is uses the variable file for each entry matching Picture*.jpg. Then it takes the file or folder and moves it to be prefixed with "vacation".

Hope that helps