/usr/sbin/cron

/usr/sbin/cron: invalid option -- '-'
Usage:
 cron [options]

Options:
 -h         print this message
 -i         daemon runs without inotify support
 -m <comm>  off, or specify preferred client for sending mails
 -n         run in foreground
 -f         run in foreground, the same as -n
 -p         permit any crontab
 -P         inherit PATH from environment instead of using default value            of "/usr/bin:/bin:/usr/sbin:/sbin"
 -c         enable clustering support
 -s         log into syslog instead of sending mails
 -V         print version and exit
 -x <flag>  print debug information

Debugging flags are: ext,sch,proc,pars,load,misc,test,bit