Installation

brew install rename

See: http://plasmasturm.org/code/rename/

Regex substitution

rename 's/hello/world/' *.txt

Rename hello.txt to world.txt and so on in *.txt.

Replace extension

rename -s .png .jpg.png *.png

Replace .png with .jpg.png in *.png.

Options

-n Simulation
-l Symlink instead of rename
-i Interactive

Also see