simple release:
sed -T s/.wav"/.flac"/<test.cue>test.out.cue
multi cd release with cd-number prefix (02 in this example):
sed -T -e s/.wav"/.flac"/ -e "s/FILE \"/FILE \"02 /" <test.cue>test.out.cue
sed is available for mostly any computing platform you can imagine. enjoy it’s full potential.