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devxtech · #1 (**permalink**) 20-11-2007, 11:01 PM

I have a script, which gathers input from the user, and I want to validate an IP that is entered. How can I validate an IP to make sure it is indeed an IP address without having to echo it out and run grep + regular expression on the variable?

devxtech · #2 (**permalink**) 21-11-2007, 01:52 AM

Got it figured out. For reference for anyone else here is what I did.

PHP Code:


			
IP_ADDR_VAL=(echo "$ipadd | grep -Ec ^(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])'")
if ! [ IP_ADDR_VAL == 0 ]; then
    echo -e "Bad IP address: $ipadd\nTry again with correct IP Address.\nNo data has been entered into DNS."
    exit 2
fi

nixcraft · #3 (**permalink**) 21-11-2007, 11:07 AM

Yup using sed or grep or awk you can validate ip. There is also command but I don't remember its name.

sanjustudy · #4 (**permalink**) 21-11-2007, 02:53 PM

Hi,
it depends on the OS your using u need to define the hard code format for Windows/Linux for recoginsation of IP address for eg: in linux it will be always of type
192.168.12.200 like that but it changes for windows,so better have switch cases and using string format condition but i prefer regexp more it works effectively.

Regards,
Sanju

devxtech · #5 (**permalink**) 21-11-2007, 09:41 PM

I made a correction in the script. Use the following for reference if anyone needs to.

PHP Code:


			
IP_ADDR_VAL=$(echo "$ipadd" | grep -Ec '^(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])')

if [ $IP_ADDR_VAL -eq 0 ]; then
    echo -e "*** Bad ip address: $ipadd\nTry again with correct IP Address.\nNo data has been entered into DNS."
    exit 2
fi

raj · #6 (**permalink**) 21-11-2007, 11:02 PM

wow! thanks dude for sharing the soultion

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