Ran export TMPDIR=~/tmp/ and it broke my node app, can I revert the tmp folder to the default folder?
TMPDIR needs to point to an existing, user-writable directory. So setting it to ~/tmp is fine as long as ~/tmp actually exists.

By default it points to /var/folders/_d/_SOMERANDOMLOOKINGSTRING/T/ to ensure that every user has their private temp folder. If for whatever reason you loose the definition you can run find /var/folders/_d -user $(whoami) -type d -maxdepth 1 to check that it still exists, and then do

export TMPDIR="$(find /var/folders/_d -user $(whoami) -type d -maxdepth 1)"


to set it back.

In case it doesn't exist any more (which is unlikely as it is protected by SIP), either reboot to have it recreated or run (all three lines)

export TMPDIR=/tmp
export TMPDIR="$(mktemp -d)"
chmod 700 "${TMPDIR}"


to create and assign a new temp folder.