how to read the contents of two files line by line and compare the line by line?

Shell Programming and Scripting
1

Hi All,

I'm trying to figure out which are the trusted-ips and which are not using a script file.. I have a file named 'ip-list.txt' which contains some ip addresses and another file named 'trusted-ip-list.txt' which also contains some ip addresses. I want to read a line from 'trusted-ip-list.txt' file and check whether the read value exists in 'ip-list.txt' file and write some log info to some other file named 'checked-trust.log' file.

Here is the code i'm trying.. But I'm not able to do so :confused: :wall:..

trust_file=trusted-ip-list.txt
ip_file=ip-list.txt

while ip= read -r line
do
       test=`grep -w "$line" $ip_file`
       echo " "
       if [ "$ip" -e "$test" ] ; then
           echo "Trusted access at `date` by $line" > checked-trust.log
       else
           echo "Untrusted access at `date` by $line" > check-trust.log
       fi
done < "$trust_file"

Please help me in solving this.. Waiting for a helping hand..

2

You are not setting the variable $ip .

It seems to me you are confusing

while ip= read -r line

while IFS= read -r line

no?

although I suspect you may want to leave that out, since you are doing a word match with it and like this it will contain any spaces in the input file..

I don't know what the

echo " "

is for.. (it's not written to the log)

$ip_file could use a pair of double quotes although with the filename contained therein, this is not strictly necessary..

If you still can't get it to work, please post sample input files...

1 Like
3

I've done a small change in the code. Please find it:

trust_file=trusted-ip-list.txt
ip_file=ip-list.txt

while read ip
do
       test=`grep -w "$ip" $ip_file`
       echo "The value of test is : $test"
       if [ "$ip" = "$test" ] ; then
           echo "Trusted access at `date` by $line" > checked-trust.log
       else
           echo "Untrusted access at `date` by $line" > check-trust.log
       fi
done < $trust_file

Even though it is not working.. When I run the script, I'm getting the following output:

I'm not able to grep the $ip value from ip-list.txt file and set to "test" variable..

4

This time the variable $line does not get set.

5 
#!/bin/bash

ip_file=ip-list.txt
trust_file=trusted-${ip_file}

while read ip; do
       if grep -w "${ip}" ${ip_file}; then
            value=Trusted
       else
            value=Untrusted
       fi
       echo "${value} access at $(date) by ${ip}" >> checked-trust.log
done < ${trust_file}