Hi,

In a ks script I have written, the first arg is an IP address - I
decided to check the validity of this using a regular expression:

#Check validity of arg1
if [[ "$1" =
\b(??:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b
]]
then
echo "Arg1 is a valid IP address"
else
echo "Arg1 is invalid"
fi

The regex may not be the most effiecient, but it is right, anyway, when
I run the script, I get:

../scriptabc.ksh: syntax error at line 17 : `(' unexpected

What am I doing wrong? (I am relatively new to ksh)

Thanks in advance

Forgot to mention that line 17 is the line with the regular expression!!