Cross check between two files

#!/bin/bash

largo=`wc -l ip|awk '{print $1}'`
echo "Direccion IP |        Dueno">salida.txt
echo "--------------------------------">>salida.txt
for ((i=1;i<=largo;i++))
    do
        ip=$(sed -n ""$i"p" ip|awk '{print $1}')
        owner=`whois $ip|grep owner:`
        dueno=${owner#*owner:}
        echo "$ip | $dueno" >> salida.txt
    done
more salida.txt

Read a file line by line and separating from fields

#!/bin/bash

largo=`wc -l ip|awk '{print $1}'`
echo "Direccion IP |        Dueno">salida.txt
echo "--------------------------------">>salida.txt
for ((i=1;i<=largo;i++))
    do
        ip=$(sed -n ""$i"p" ip|awk '{print $1}')
        owner=`whois $ip|grep owner:`
        dueno=${owner#*owner:}
        echo "$ip | $dueno" >> salida.txt
    done
more salida.txt