external-program provides a largely-portable wrapper for running programs external to the Lisp process (ie - exec()).
See also: uiop, executor
ASDF-install package (obsolete) http://common-lisp.net/project/external-program/releases/external-program_latest.tar.gz
Personal opinion: external-program had its time, but uiop:run-program is more portable, more robust, more featureful, more widely used, and is already part of your implementation-provided asdf
3. Use uiop
instead. — Fare Rideau