Delete empty subfolders, keep parent folder

Question

When I use

find /home/user/parentdir -type d -empty -delete

it looks recursively for empty subfolders inside /home/user/parentdir and deletes them. But if /home/user/parentdir is also empty, it deletes the parentdir folder too, which is undesirable for me.

I want to keep this parentdir to rsync some files to backup or cloud. After processing, I need to delete the empty folders, but seems unproductive to recreate parentdir every time.

Any suggestions to keep parentdir? I thought about creating a .nocopy file inside it and exclude it from rsync, but looks like overkill. Is there a more elegant way?

Answer 1

Simply do find /home/user/parentdir -mindepth 1 -type d -empty -delete.

Look:

$ mkdir -p test1/test2
$ find test1 -type d
test1
test1/test2
$ find test1 -mindepth 1  -type d
test1/test2

The find /home/user/parentdir/* in AmourK’s answer is undesirable when there are a lot of files and it is overcomplicated.

Answer 2

By adding /* to the end of parentdir, you are performing the action on all subdirs of parentdir rather than on parentdir itself. And so in the same way /home/user/ is not deleted in the old command, parentdir will not be not be deleted in the command below. * is called a glob operator and it matches any string of characters.

find /home/user/parentdir/* -type d -empty -delete

Answer 3

if you have php-cli installed,

printf %s $(pwd) | php -r 'function f(string $dir){var_dump($dir);$dir.=DIRECTORY_SEPARATOR;foreach(glob("$dir*",GLOB_ONLYDIR) as $d){f($d);}global $original;if(substr($dir,0,-strlen(DIRECTORY_SEPARATOR))!==$original && empty(glob("$dir*"))){rmdir($dir);}}f(($original=stream_get_contents(STDIN)));'

Answer 4

When you only need one level (leaving a parent folder, but deleting empty child folders), an easy trick is to use rmdir.

rmdir parent/*

Deletes all empty subfolders, but only prints an error for files and non-empty folders.

This does not work recursively, but when knowing your folder structure it may be the fastest way to do something like

rmdir parent/*/*/* # deletes parent/a/b/c when empty
rmdir parent/*/* # deletes parent/a/b when it is now empty
rmdir parent/* # deletes parent/a when it is now empty

Advantage: Easy to remember, fast to type, little potential for choosing a wrong parameter.
Disadvantage: Less flexible, possibly a lot of error messages in your terminal.