Running command recursively in linux

Question

I'm trying to come up with a command that would run mp3gain FOLDER/SUBFOLDER/*.mp3 in each subfolder, but I'm having trouble understanding why this command doesn't work:

find . -type d -exec mp3gain \"{}\"/*.mp3 \;

When run, I get error Can't open "./FOLDER/SUBFOLDER"/*.mp3 for reading for each folder and subfolder.

If I run command manually with mp3gain "./FOLDER/SUBFOLDER"/*.mp3 it works. What's going wrong?

noqqe · Answer 1 · 2013-01-27T15:54:42.663

3

If you have a fixed data structure like

folder1/subfolder1/
folder1/subfolder2/
folder2/subfolder1/
[...]

and using zsh or bash version >=4.0 you could try

mp3gain **/*.mp3

But to make sure check the output of

ls **/*.mp3

before you are getting serious with mp3gain.

edited Jan 27 '13 at 15:54

answered Jan 26 '13 at 11:13

noqqe

162
8

The `**` syntax (which I love) is new in `bash` 4 or `zsh`. Some shells don't have it. And `ls **/*.mp3` is then enough (for those shells understanding `**`) – Basile Starynkevitch Jan 26 '13 at 11:55

score 1 · Accepted Answer · answered Jan 26 '13 at 09:25

1

When you run mp3gain "./FOLDER/SUBFOLDER"/*.mp3 from your shell, the *.mp3 is getting expanded by the shell before being passed to mp3gain. When find runs it, there is no shell involved, and the *.mp3 is getting passed literally to mp3gain. The latter has no idea how to deal with wildcards (because normally it doesn't have to).

answered Jan 26 '13 at 09:25

NPE

486,780
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Thank you! Wrapping exec command with `-exec sh -c 'mp3gain "{}"/*.mp3' \;` worked. – laite Jan 26 '13 at 11:59

score 0 · Answer 3 · answered Jan 26 '13 at 09:25

Hmmm. Just tried this to test how the directory is parsed by replacing mp3gain with echo and it works:

find . -type d -exec echo {}\/\*.mp3 \;

Try running your version of the command but with echo to see the file output for yourself:

find . -type d -exec echo \"{}\"/*.mp3 \;

Seems the quotes get in the way in your original command.

score 0 · Answer 4 · edited Dec 15 '13 at 22:44

0

this works...

find /music -name *mp3 -exec mp3gain -r -k {} \;

edited Dec 15 '13 at 22:44

Andrea

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answered Dec 15 '13 at 22:24

anon

1

Running command recursively in linux

4 Answers4