# It goes something like: ls the packages, grep the names, make them unique,
# find duplicates, sort by version, remove old versions.
#
# See that gsort (macOS)? that's $ brew install coreutils
ls $(yarn cache dir) | grep -oE "^(npm-[a-z-]+)" | uniq | while read -r i; do ls -1d "$i"* | grep -cE "$i\d" | { read -r c; if (( c > 1 )); then ls -1d "$i"* | grep -E "$i\d" | gsort -Vr | tail -n +2 | xargs rm -r; fi }; done