CODEWITHSUNDEEP
linuxbashshell
user2133809
user2133809

Reputation: 73

Create a bash script to delete folders which do not contain a certain filetype

I have recently run into a problem.

I used a utility to move all my music files into directories based on tags. This left a LOT of almost empty folders. The folders, in general, contain a thumbs.db file or some sort of image for album art. The mp3s have the correct album art in their new directories, so the old ones are okay to delete.

Basically, I need to find any directories within D:/Music/ that:

-Do not have any subdirectories

-Do not contain any mp3 files

And then delete them.

I figured this would be easier to do in a shell script or bash script or whatever else linux/unix world than in Windows 8.1 (HAHA).

Any suggestions? I'm not very experienced writing scripts like this.

Upvotes: 3

Views: 2515

Answers (3)

mselimata
mselimata

Reputation: 11

Found the issue here, similar to @user2133809 these commands deleted the necessary files not the ones that must be deleted. It seems there might be a difference on find command which may not always successfully lists the attributes. But usage of sed to find the necessary file extension helped me to manage to form a list of directories containing the files that I want to keep. Combining the solution above with this solution provides a clear pipeline to remove the list of unwanted files and securely delete them. my working script changes creation of the non-empty-dirs.tmp like this:

find . -type f -name '*.mp3*' | sed -r 's|/[^/]+$||' |sort |uniq > non-empty-dirs.tmp

I don't have enough reputation @James but thank you for sharing this concise answer.

Upvotes: 1

James
James

Reputation: 4681

Here's the short story...

find . -name '*.mp3' -o -type d -printf '%h\n' | sort | uniq > non-empty-dirs.tmp
find . -type d -print | sort | uniq > all-dirs.tmp
comm -23 all-dirs.tmp non-empty-dirs.tmp > dirs-to-be-deleted.tmp

less dirs-to-be-deleted.tmp

cat dirs-to-be-deleted.tmp | xargs rm -rf

Note that you might have to run all the commands a few times (depending on your repository's directory depth) before you're done deleting all recursive empty directories...

And the long story goes...

You can approach this problem from two basic perspective: either you find all directories, then iterate over each of them, check if it contain any mp3 file or any subdirectory, if not, mark that directory for deletion. It will works, but on large very large repositories, you might expect a significant run time.

Another approach, which is in my sense much more interesting, is to build a list of directories NOT to be deleted, and subtract that list from the list of all directories. Let's work the second strategy, one step at a time...

First of all, to find the path of all directories that contains mp3 files, you can simply do:

find . -name '*.mp3' -printf '%h\n' | sort | uniq

This means "find any file ending with .mp3, then print the path to it's parent directory".

Now, I could certainly name at least ten different approaches to find directories that contains at least one subdirectory, but keeping the same strategy as above, we can easily get...

find . -type d -printf '%h\n' | sort | uniq

What this means is: "Find any directory, then print the path to it's parent."

Both of these queries can be combined in a single invocation, producing a single list containing the paths of all directories NOT to be deleted.. Let's redirect that list to a temporary file.

find . -name '*.mp3' -o -type d -printf '%h\n' | sort | uniq > non-empty-dirs.tmp

Let's similarly produce a file containing the paths of all directories, no matter if they are empty or not.

find . -type d -print | sort | uniq > all-dirs.tmp

So there, we have, on one side, the complete list of all directories, and on the other, the list of directories not to be deleted. What now? There are tons of strategies, but here's a very simple one:

comm -23 all-dirs.tmp non-empty-dirs.tmp > dirs-to-be-deleted.tmp

Once you have that, well, review it, and if you are satisfied, then pipe it through xargs to rm to actually delete the directories.

cat dirs-to-be-deleted.tmp | xargs rm -rf

Upvotes: 0

Zombo
Zombo

Reputation: 1

This should get you started

find /music -mindepth 1 -type d |
while read dt
do
  find "$dt" -mindepth 1    -type d | read && continue
  find "$dt" -iname '*.mp3' -type f | read && continue
  echo DELETE $dt
done

Upvotes: 4

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