Add prefix to multiple files at once

gistfile1.txt

# Add office- prefix to all files on a directory
ls | xargs -I {} mv {} office-{}

# Add office- prefix to all .js files on a directory
ls | grep .js | xargs -I {} mv {} office-{}

More information:
http://stackoverflow.com/questions/6329505/how-to-rename-all-file-in-a-folder-with-a-prefix-in-a-single-unix-command