NAME

       chronic - runs a command quietly unless it fails

SYNOPSIS

       chronic [-ev] COMMAND...

DESCRIPTION

       chronic runs a command, and arranges for its standard out and standard error to only be
       displayed if the command fails (exits nonzero or crashes).  If the command succeeds, any
       extraneous output will be hidden.

       A common use for chronic is for running a cron job. Rather than trying to keep the command
       quiet, and having to deal with mails containing accidental output when it succeeds, and
       not verbose enough output when it fails, you can just run it verbosely always, and use
       chronic to hide the successful output.

               0    1 * * * chronic backup # instead of backup >/dev/null 2>&1
               */20 * * * * chronic -ve my_script # verbose for debugging

OPTIONS

       -v  Verbose output (distinguishes between STDOUT and STDERR, also reports RETVAL)

       -e  Stderr triggering. Triggers output when stderr output length is non-zero.  Without -e
           chronic needs non-zero return value to trigger output.

AUTHOR

       Copyright 2010 by Joey Hess <id@joeyh.name>

       Original concept and "chronic" name by Chuck Houpt.  Code for verbose and stderr trigger
       by Tomas 'Harvie' Mudrunka 2016.

       Licensed under the GNU GPL version 2 or higher.