Check for IP validity

Question

How do I check the validity of an IP address in a shell script, that is within the range 0.0.0.0 to 255.255.255.255?

Answer 1

I prefer to use ipcalc to do this, as long as my script doesn't have to be portable.

ipcalc 1.1.1.355                                                                         
INVALID ADDRESS: 1.1.1.355

Address:   192.168.1.1          11000000.10101000.00000001. 00000001
Netmask:   255.255.255.0 = 24   11111111.11111111.11111111. 00000000
Wildcard:  0.0.0.255            00000000.00000000.00000000. 11111111
=>
Network:   192.168.1.0/24       11000000.10101000.00000001. 00000000
HostMin:   192.168.1.1          11000000.10101000.00000001. 00000001
HostMax:   192.168.1.254        11000000.10101000.00000001. 11111110
Broadcast: 192.168.1.255        11000000.10101000.00000001. 11111111
Hosts/Net: 254                   Class C, Private Internet

There is a great page showing how to use it in scripting, etc, here: SleeplessBeastie's Notes