command() @click.option('--rolls', callback=validate_rolls, default='1d6') def roll(rolls): click.echo('Rolling a %d-sided dice %d time(s)' % rolls) if __name__ == '__main__': roll() And what it looks like: [OPTIONS] Error: Invalid value for "--rolls": rolls need to be in format NdM $ roll --rolls=2d12 Rolling a 12-sided dice 2 time(s) 1.6 Arguments Arguments work similarly to options but are positional

I:43 360 outil de mesure de la bande passante du protocole Internet ifstat V:0, I:7 60 InterFace STATistics Monitoring (surveillance des statistiques de l’ interface) bmon V:1, I:18 144 surveillance portable (149.20.4.15) 1472(1500) bytes of data. ping: local error: message too long, mtu=1460 --- ping statistics --- 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms $ ping -4 -c 1 -s 1440 bytes from klecker-misc.debian.org (130.89.148.77): icmp_seq=1 ttl=50 time=325 ms --- ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 325.318/325