Hi, I have a small script which uses egrep and a set of regexes to validate an IP address, however, i want to make it so that if somebody puts a leading space in front of the IP address to be validated it will fail, so this is my script
Code:
#!/bin/bash
#function
ip_checker() {
result=$( echo $1 | egrep "(^[01]?[0-9][0-9]?|2[0-4][0-9]|25[0-4])\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-4])\.([01]?[0-9][0-9]?|2[0-4]
[0-9]|25[0-4])\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-4]$)" )
if [ -z $result ]; then
echo " "
echo "That IP is invalid"
exit 1
else
echo "IP looks fine"
fi
}
IP=" 192.168.1.2"
ip_checker $IP
notice the space before the IP that I have set in $IP variable (in bold above)
this returns
Code:
# ./test.sh
IP looks fine
its the same however many spaces i put in front of the IP, however, if i put a different character in front of the IP e.g
Code:
IP="x192.168.1.2"
ip_checker $IP
it fails as expected
Code:
# ./test.sh
That IP is invalid
its just those pesky spaces .. as you can see I have entered a ^ in the regex at the beginning but that seems to be ignored
, most probably even sooner, with the call to ip_checker
Put double quotes around the $1/$IP and your script will fail as expected.
Just as a side node: most UNIX shells (all that I know) use spaces as argument seperators and strip away any that aren't explicitly literal (using quotes). There's usually no need to check for them manually.
if you are able to use Perl and install module Data::Validate::IP, it makes your life much easier
Code:
#!/usr/bin/perl
use Data::Validate::IP qw(is_ipv4);
$ip = "192.168.0.1";
if(is_ipv4($ip)){
print "$ip is valid ip address\n";
}else{
print "$ip is an ip address\n";
}
$ip = "1.1.257.2";
if(is_ipv4($ip)){
print "$ip is valid ip address\n";
}else{
print "$ip is Not an ip address\n";
}
output
Code:
# ./test.pl
192.168.0.1 is valid ip address
1.1.257.2 is Not an ip address
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