I\'ve successfully used the following sed command to search/replace text in Linux:
sed
sed -i \'s/old_link/new_link/g\' *
However,
Your Mac does indeed run a BASH shell, but this is more a question of which implementation of sed you are dealing with. On a Mac sed comes from BSD and is subtly different from the sed you might find on a typical Linux box. I suggest you man sed.
man sed