Bash: find | sed | xargs rm not working, but rm does - bash

Question

I'm trying to remove all .js and .js.map files from any sub-directory of src called __tests__.
$ find . -path './src/**' -name __tests__ | # find subdirectories
> sed -E 's/([^ ]+__tests__)/\1\/*.js \1\/*.js.map/g' | # for each subdirectory, concat *.js and *.js.map
> xargs rm # remove files
This fails with the following errors:
rm: cannot remove './src/game/__tests__/*.js': No such file or directory
rm: cannot remove './src/game/__tests__/*.js.map': No such file or directory
rm: cannot remove './src/helpers/__tests__/*.js': No such file or directory
rm: cannot remove './src/helpers/__tests__/*.js.map': No such file or directory
However, if I change my xargs rm to xargs echo rm, copy and paste the output, and run it, it works.
$ find . -path './src/**' -name __tests__ | sed -E 's/([^ ]+__tests__)/\1\/*.js \1\/*.js.map/g' |
> xargs echo rm # echo command to remove files
rm ./src/game/__tests__/*.js ./src/game/__tests__/*.js.map ./src/helpers/__tests__/*.js ./src/helpers/__tests__/*.js.map
$ rm ./src/game/__tests__/*.js ./src/game/__tests__/*.js.map ./src/helpers/__tests__/*.js ./src/helpers/__tests__/*.js.map
Wrapping the output of my echo in $(...) and prepending rm results in the same error as before.
$ rm $(find . -path './src/**' -name __tests__ | sed -E 's/([^ ]+__tests__)/\1\/*.js \1\/*.js.map/g' | xargs echo rm
rm: cannot remove './src/game/__tests__/*.js': No such file or directory
rm: cannot remove './src/game/__tests__/*.js.map': No such file or directory
rm: cannot remove './src/helpers/__tests__/*.js': No such file or directory
rm: cannot remove './src/helpers/__tests__/*.js.map': No such file or directory
What am I doing wrong?
I doubt it matters, but I'm using GitBash on Windows.

Answer 1

First, to explain the issue: In find | sed | xargs rm, the shell only sets up communication between those programs, but it doesn't actually process the results in any way. That's a problem here because *.js needs to be expanded by a shell to replace it with a list of filenames; rm treats every argument it's given as a literal name. (This is unlike Windows, where programs do their own command-line parsing and glob expansion).
Arguably, you don't need find here at all. Consider:
shopt -s globstar # enable ** as a recursion operator
rm ./src/**/__tests__/*.js{,.map} # delete *.js and *.js.map in any __tests__ directory under src
...or, if you do want to use find, let it do the work of coming up with a list of individual files matching *.js, instead of leaving that work to happen later:
find src -regextype posix-egrep -regex '.*/__tests__/[^/]*[.]js([.]map)?' -delete

Answer 2

You need to have your globs (*) expanded. File name expansion is performed by the shell on UNIX, not by rm or other programs. Try:
.... | xargs -d $'\n' sh -c 'IFS=; for f; do rm -- $f; done' sh
...to explain this:
The -d $'\n' ensures that xargs splits only on newlines (not spaces!), and also stops it from treating backslashes and quotes as special.
sh -c '...' sh runs ... as a script, with sh as $0, and subsequent arguments in $1, etc; for f; will thus iterate over those arguments.
Clearing IFS with IFS= prevents string-splitting from happening when $f is used unquoted, so only glob expansion happens.
Using the -- argument to rm ensures that it treats subsequent arguments as filenames, not options, even if they start with dashes.
That said, if you have really a lot of files for each pattern, you might run into an "argument list too long", even though you are using xargs.
Another caveat is that filenames containing newlines can potentially be split into multiple names (depending on the details of the version of find you're using). A way to solve this that will work with all POSIX-compliant versions of find might be:
find ./src -type d -name __tests__ -exec sh -c '
for d; do
rm -- "$d"/*.js{,.map}
done
' sh {} +