For more info please refer to docs >> changes >> fontawesome

You can use this script to update your Fontawesome icons from v3.x to v4.x
If you want to use a name other than "ace-icon" for your icons, make sure to modify `ace_icon` variable inside "icon.js"

Options are:
  path: Path to the folder or file you want to update.
  ext: If specified only this extensions will be updated.

node icon.js --path=".../html/myfile.html"
node icon.js --path=".../mydir/"
node icon.js --path="path/to/folder" --ext="html|php|js"

Note the three dots "..." when referring to upper level folders!

Please see documentation, Changes/FontAwesome  section