Perform an action in every sub-directory using Bash - bash

Question

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?

Answer 1

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

Answer 2

for D in `find . -type d`
do
//Do whatever you need with D
done

Answer 3

The simplest non recursive way is:
for d in */; do
echo "$d"
done
The / at the end tells, use directories only.
There is no need for
find
awk
...

Answer 4

Use find command.
In GNU find, you can use -execdir parameter:
find . -type d -execdir realpath "{}" ';'
or by using -exec parameter:
find . -type d -exec sh -c 'cd -P "$0" && pwd -P' {} \;
or with xargs command:
find . -type d -print0 | xargs -0 -L1 sh -c 'cd "$0" && pwd && echo Do stuff'
Or using for loop:
for d in */; { echo "$d"; }
For recursivity try extended globbing (**/) instead (enable by: shopt -s extglob).
For more examples, see: How to go to each directory and execute a command? at SO

Answer 5

Handy one-liners
for D in *; do echo "$D"; done
for D in *; do find "$D" -type d; done ### Option A
find * -type d ### Option B
Option A is correct for folders with spaces in between. Also, generally faster since it doesn't print each word in a folder name as a separate entity.
# Option A
$ time for D in ./big_dir/*; do find "$D" -type d > /dev/null; done
real 0m0.327s
user 0m0.084s
sys 0m0.236s
# Option B
$ time for D in `find ./big_dir/* -type d`; do echo "$D" > /dev/null; done
real 0m0.787s
user 0m0.484s
sys 0m0.308s

Answer 6

find . -type d -print0 | xargs -0 -n 1 my_command

Answer 7

This will create a subshell (which means that variable values will be lost when the while loop exits):
find . -type d | while read -r dir
do
something
done
This won't:
while read -r dir
do
something
done < <(find . -type d)
Either one will work if there are spaces in directory names.

Answer 8

You could try:
#!/bin/bash
### $1 == the first args to this script
### usage: script.sh /path/to/dir/
for f in `find . -maxdepth 1 -mindepth 1 -type d`; do
cd "$f"
<your job here>
done
or similar...
Explanation:
find . -maxdepth 1 -mindepth 1 -type d :
Only find directories with a maximum recursive depth of 1 (only the subdirectories of $1) and minimum depth of 1 (excludes current folder .)

Answer 9

the accepted answer will break on white spaces if the directory names have them, and the preferred syntax is $() for bash/ksh. Use GNU find -exec option with +; eg
find .... -exec mycommand +; #this is same as passing to xargs
or use a while loop
find .... | while read -r D
do
# use variable `D` or whatever variable name you defined instead here
done

Answer 10

if you want to perform an action INSIDE the folder and not ON folder.
Explanation: You have many pdfs and you would like to concetrate them inside a single folder.
my folders
AV 001/
AV 002/
for D in *; do cd "$D"; # VERY
DANGEROUS COMMAND - DONT USE
#-- missing "", it will list files too. It can go up too.
for d in */; do cd "$d"; echo $d; cd ..; done; # works
succesfully
for D in "$(ls -d */)"; do cd "$D"; done; #
bash: cd: $'Athens Voice 001/\nAthens Voice 002/' - there is no such
folder
for D in "$(*/)"; do cd "$D"; done; # bash: Athens
Voice 001/: is folder
for D in "$(`find . -type d`)"; do cd $D; done; # bash: ./Athens: there is no such folder or file
for D in *; do if [ -d "${D}" ] then cd ${D}; done; # many
arguments