Write Dollar sign in sed command pattern inside makefile

Question

I have a makefile that contains this command:

sed '/^$/d'

when I ran it I got:

sed '/^d'
sed: -e expression #1, char 3: unterminated address regex

looks like it interprets the dollar sign, how can I prevent that from happening?

Answer 1

You have to double all dollar signs in a recipe, otherwise make treats them as introducing a make variable:

sed '/^$$/d'

If you search for "dollar sign makefile" or similar you'll find tens if not hundreds of answers to virtually this exact question.