Perform an action in every sub-directory using Bash

Asked 22/10, 2010 at 20:15 Answered 19/8, 2022 at 3:10

232

I am working on a script that needs to perform an action in every sub-directory of a specific folder.

What is the most efficient way to write that?

Disused answered 22/10, 2010 at 20:15 Comment(2)

Please consider coming back through and reevaluating answers for correctness -- you've got an accepted answer getting a lot of views despite major bugs (f/e, running it over a directory where someone previously ran mkdir 'foo * bar' will cause foo and bar to be iterated over even if they don't exist, and the * will be replaced with a list of all filenames, even non-directory ones). – Ewe 8/5, 2018 at 16:46

...even worse is if someone ran mkdir -p '/tmp/ /etc/passwd /' -- if someone runs a script following this practice on /tmp to, say, find directories to delete, they could end up deleting /etc/passwd. – Ewe 8/5, 2018 at 16:48

189

for D in $(find . -mindepth 1 -maxdepth 1 -type d); do
    //Do whatever you need with D
done

Friedman answered 22/10, 2010 at 20:29 Comment(10)

this will break on white spaces – Cadaverous 22/10, 2010 at 23:16

Also, note you need to tweak the find params if you want recursive or non-recursive behavior. – Coaptation 23/10, 2010 at 16:34

The above answer gave me the self directory as well, so the following worked a bit better for me: find . -mindepth 1 -type d – Uriniferous 6/10, 2014 at 16:48

@JoshC, both variants will break the directory created by mkdir 'directory name with spaces' into four separate words. – Ewe 8/5, 2018 at 16:42

I needed to add -mindepth 1 -maxdepth 1 or it went too deep. – Butcherbird 1/5, 2019 at 14:1

The same in a single line (can be run at command-line): for D in `find . -type d`; do //Do whatever you need with D; done – Lody 12/6, 2019 at 11:28

@Butcherbird just replace both with -depth 1 – Iaea 7/3, 2021 at 6:6

@Iaea -depth Process each directory's contents before the directory itself. I think it isn't a replace for mindepth and maxdepth. – Eskilstuna 30/9, 2021 at 14:26

@Eskilstuna You are correct that it would traverse in a different order. I might have misunderstood the desired outcome, thanks for bringing this up :) – Iaea 4/10, 2021 at 13:14

If using find I think one might as well get rid of the for loop and use find with its exec argument instead. – Displode 24/3, 2022 at 8:20

338

A version that avoids creating a sub-process:

for D in *; do
    if [ -d "${D}" ]; then
        echo "${D}"   # your processing here
    fi
done

Or, if your action is a single command, this is more concise:

for D in *; do [ -d "${D}" ] && my_command; done

Or an even more concise version (thanks @enzotib). Note that in this version each value of D will have a trailing slash:

for D in */; do my_command; done

Metalinguistic answered 22/10, 2010 at 20:33 Comment(8)

You can avoid the if or [ with: for D in */; do – Foamy 23/10, 2010 at 6:24

+1 because directory names don't begin with ./ as opposed to accepted answer – Biopsy 5/2, 2014 at 11:0

This one is correct even up to spaces in the directory names +1 – Werewolf 4/5, 2014 at 19:49

There is one problem with the last command: if you are in a directory without subdirectories; it will return "*/". So better use the second command for D in *; do [ -d "${D}" ] && my_command; done or a combination of the two latest: for D in */; do [ -d $D ] && my_command; done – Frigate 2/10, 2014 at 6:12

Note that this answer ignores hidden directories. To include hidden directories use for D in .* *; do instead for D in *; do. – Travers 18/5, 2016 at 17:34

note for noobs like me that if you're wanting to do this on a directory that isn't the current, the syntax is for D in ./directory/*; do – Towhee 7/8, 2019 at 20:53

use ${D%/*} instead of $D to trim the trailing slash. – Whitewing 5/10, 2019 at 13:4

@Whitewing ${D%/} is probably safer so extra characters after the / aren't accidentally removed. – Metalinguistic 5/10, 2019 at 20:3

189

for D in $(find . -mindepth 1 -maxdepth 1 -type d); do
    //Do whatever you need with D
done