Convert FLAC to ALAC/AAC on a Mac

Step 1: install flac via Homebrew

brew install flac

Step 2: decode FLAC to AIFF

cd path/to/directory/with/files/to/convert
for i in *.flac; do
  flac -d --force-aiff-format "$i"
done

Step 3: copy AIFF files to iTunes
Step 4: convert in iTunes to desired (ALAC/AAC) format