Early exit on TERM=unknown
Early exit on TERM=unknown

When running in non-interactive environments sometimes the TERM is set to 'unknown' rather than being unset, e.g. https://askubuntu.com/questions/1091553/how-do-i-fix-error-opening-terminal-unknown-on-ubuntu-server
milouse/liquidprompt,nojhan/liquidprompt,jaesivsm/liquidprompt,laurentbardin/liquidprompt