Cronic is a small shim shell script for wrapping cron jobs so that cron only
sends email when an error has occurred. Cronic defines an error as any
non-trace error output or a non-zero result code. Cronic filters Bash
execution traces (or anything matching PS4) from the error output, so jobs can
be run with execution tracing to aid forensic debugging.

WWW: http://habilis.net/cronic