My data file look like tis
field1:field2:field3:field4:field5

I wan to compare field 2 with 1 variable and if match change the details of it.

How can i do it?

I used to do it like tis:
#in shell script

checkSerial() {
while [ "$counter" != "correct" ]
do
echo "  \c"
echo "  \c" ; read serial
awk -v awk_serial=$serial aSerial.awk data.dat | read counter
echo $counter
if test "$counter" != "correct"
then
echo "  Serial number already exist!\c"
fi
done
counter=""
}

#aSerial.awk
BEGIN { FS = ":" }

{ if ( $2 == awk_serial )
flags=1
}

END { if ( flags != 1 )
printf "correct"
}

Pls correct my mistake coz this seems like dun work....thx