Bash renames, for future reference. Just wanted something quick, I'm sure there is a better way.

gistfile1.sh

#!/bin/bash

for file in *.coffee; do
  filename=$(basename "$file")
  ext="${filename##*.}"
  filename="${filename%.*}"
  git mv "$file" "$filename.js.$ext"
done

for lessfile in *.less; do
  filename=$(basename "$lessfile")
  ext="${filename##*.}"
  filename="${filename%.*}"
  git mv "$lessfile" "$filename.css.$ext"
done