Perform an action in every sub-directory using Bash

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?

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

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

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
• ...

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

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