The -q flag for the command in a crontab(5) entry was introduced in revision 1.8 of src/usr.sbin/cron/entry.c back in 2001, but never documented.
(Sorry, I'm no hero with mdoc, so not sure if the markup is correct.) Wouter Index: usr.sbin/cron/crontab.5 =================================================================== RCS file: /cvs/src/usr.sbin/cron/crontab.5,v retrieving revision 1.33 diff -u -p -u -r1.33 crontab.5 --- usr.sbin/cron/crontab.5 30 Jan 2014 20:02:42 -0000 1.33 +++ usr.sbin/cron/crontab.5 11 Oct 2016 10:59:59 -0000 @@ -194,6 +194,12 @@ after the first .Ql % will be sent to the command as standard input. .Pp +If the +.Ar command +field starts with +.Fl q , +execution will not be logged. +.Pp Commands are executed by .Xr cron 8 when the
