If you followed my [CLI improved](/2018/08/23/cli-improved) then you’ll know I’m a fan of the [fd](/2018/08/23/cli-improved#fd—find) 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.
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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](/2016/12/16/tricks-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](https://github.com/sharkdp/fd#parallel-command-execution):
-
{}: 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 -j1The 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.
Published 13-Aug 2019 under #code. [Edit this post](https://github.com/remy/remysharp.com/blob/main/public/blog/fd-trick.md)
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