If you followed my CLI improved and I'm a fan of the fd command which I'm able to use for a mass git file rename.

Doing a mass rename is typically simple in the command line (mv *.mjs *.js - though I'm not sure off the top of my head if this will recurse directories, probably not), but doing a mass rename with git is harder, especially as there's some kind of locking going on. This means that the mass git rename must be run sequentially.

In my particular recent case, I wanted to rename all instances of .mjs files (excluding node_modules) to .js. I've tried this before with xargs and kept failing but fd makes it pretty easy.

The fd command allows you execute a command against the results (similarly to xargs) and usefully fd also provides some useful additions for filename substitution:

  • {}: A placeholder token that will be replaced with the path of the search result (documents/images/party.jpg)
  • {.}: Like {}, but without the file extension (documents/images/party)
  • {/}: A placeholder that will be replaced by the basename of the search result (party.jpg)
  • {//}: Uses the parent of the discovered path (documents/images)
  • {/.}: Uses the basename, with the extension removed (party)

Armed with this information, I can find all mjs files -e mjs, and I can execute git mv with the full path to the result as the first argument and the {.} placeholder for the filename excluding the extension:

fd -e mjs -x git mv {} {.}.js -j1

The final argument (as above) is -j1 which tells fd to run the commands in a single thread (by default fd will run multiple threads - I don't recall how many) - this is important because git will lock and unlock the git metadata files upon each rename.

Otherwise, that's it. A single command to git rename.