.. # Change the extension, for example, the current directory is changed to doc txt extension:
! # / bin / bash
for f in * txt;. do mv "$ f" "$ {f / txt / doc} " ; DONE
# util-linux software package with the rename can achieve the same purpose.
! # / bin / bash
for f in * txt;. do mv "$ f" "$ {f / txt / doc} " ; DONE
# util-linux software package with the rename can achieve the same purpose.