Linux: loop all subfolder

for f in $(find ./); do if [ -d "$f" ]; then echo $f; fi; done

使用範例，將所有檔案名稱中的空白字符替換為下劃線︰
for f in $(find ./); do if [ -d "$f" ]; then cd $f; sh ~/program/sh/renamefile_spaceToUnderscore.sh ok; cd -; fi; done