How to loop over directories in Linux?

I am writing a script in bash on Linux and need to go through all subdirectory names in a given directory. How can I loop through these directories (and skip regular files)?

For example:
the given directory is /tmp/
it has the following subdirectories: /tmp/A, /tmp/B, /tmp/C

I want to retrieve A, B, C.

Solution 1:

All answers so far use find, so here's one with just the shell. No need for external tools in your case:

for dir in /tmp/*/     # list directories in the form "/tmp/dirname/"
do
    dir=${dir%*/}      # remove the trailing "/"
    echo "${dir##*/}"    # print everything after the final "/"
done

Solution 2:

cd /tmp
find . -maxdepth 1 -mindepth 1 -type d -printf '%f\n'

A short explanation:

find finds files (quite obviously)
. is the current directory, which after the cd is /tmp (IMHO this is more flexible than having /tmp directly in the find command. You have only one place, the cd, to change, if you want more actions to take place in this folder)
-maxdepth 1 and -mindepth 1 make sure that find only looks in the current directory and doesn't include . itself in the result
-type d looks only for directories
-printf '%f\n prints only the found folder's name (plus a newline) for each hit.

Et voilà!

Solution 3:

You can loop through all directories including hidden directrories (beginning with a dot) with:

for file in */ .*/ ; do echo "$file is a directory"; done

note: using the list */ .*/ works in zsh only if there exist at least one hidden directory in the folder. In bash it will show also . and ..

Another possibility for bash to include hidden directories would be to use:

shopt -s dotglob;
for file in */ ; do echo "$file is a directory"; done

If you want to exclude symlinks:

for file in */ ; do 
  if [[ -d "$file" && ! -L "$file" ]]; then
    echo "$file is a directory"; 
  fi; 
done

To output only the trailing directory name (A,B,C as questioned) in each solution use this within the loops:

file="${file%/}"     # strip trailing slash
file="${file##*/}"   # strip path and leading slash
echo "$file is the directoryname without slashes"

Example (this also works with directories which contains spaces):

mkdir /tmp/A /tmp/B /tmp/C "/tmp/ dir with spaces"
for file in /tmp/*/ ; do file="${file%/}"; echo "${file##*/}"; done

Solution 4:

Works with directories which contains spaces

Inspired by Sorpigal

while IFS= read -d $'\0' -r file ; do 
    echo $file; ls $file ; 
done < <(find /path/to/dir/ -mindepth 1 -maxdepth 1 -type d -print0)

Original post (Does not work with spaces)

Inspired by Boldewyn: Example of loop with find command.

for D in $(find /path/to/dir/ -mindepth 1 -maxdepth 1 -type d) ; do
    echo $D ;
done