delete string in text and overwrite file

hi guys, i would like to delete <br /> in all txt files found by my rule using shellscript. after googling and trying for nearly 30 (thirty) hours i have no other option than ask you pros out there. would be more than happy if someone could help me! thanks!

This isn't really Hazel specific but maybe someone else can provide assistance on this. You might have better luck on a shell scripting forum.