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boredazfcuk / docker-icloudpd

An Alpine Linux container for the iCloud Photos Downloader command line utility
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Possible Optimization: Combine chown/chgrp #500

Closed lonevvolf closed 4 months ago

lonevvolf commented 5 months ago

I've seen that the calls to chown/chgrp take quite some time if you have lots of files. chown supports setting the owner and group in a single command: https://linux.die.net/man/1/chown

ie. chown tito:editors file.txt

Could the two calls be combined into one to help improve the speed?

boredazfcuk commented 5 months ago

chown supports setting the owner and group in a single command

Correct.

Could the two calls be combined into one to help improve the speed?

This was the original behaviour of the container but unfortunately it was too slow. chowning all the files on a large library takes a looooong time. To optimise this, I use find to check for all the files which do not have correct owner and then only chown those files. Then I use find to get all the files which do not have the correct group, and chgrp those files.

Unfortunately, combining the two find parameters into a single command doesn't produce the required results. find parameters are taken as and rather than or so:

find . ! -user "${user_id}" ! -group "${group_id}" -exec chown "${user_id}:${group_id}" {} +

only finds files that have both user and group set incorrectly. It will not find files for which only one of these is wrong.

If you know of a way to make find show files that have one of the two properties set incorrectly, then it may be possible to improve the performance, but as it stands, moving back to a single chown command will only decrease performance.