Say I have folders:
img1/
img2/
How do I delete those folders using regex from Linux terminal, that matches everything starts with img?
Use find to filter directories
$ find . -type d -name "img*" -exec rm -rf {} \;
As it was mentioned in a comments this is using shell globs not regexs. If you want regex
$ find . -type d -regex "\./img.*" -exec rm -rf {} \;