compare the hostnames in /etc/hosts with the result of nslookup on a ip from /etc/hos
 

I want to compare the hostnames in /etc/hosts with the result of nslookup on a ip from /etc/hosts.

So i want to put each ip from /etc/hosts in a variable and then do a nslookup on that ip. And after that compare the hostname wich comes up after running nslookup to the hostname in the /etc/hosts file.

Shell scripting is still quite new for me so i don't know really where to begin.

I did something like this:
cat /etc/hosts | grep -v # | while read LINE do echo $LINE done

but i don't know how print out line by line.

Is there a other way to do this?
Please give me a push in the right direction.

Reading lines instead of tokens trips me up too...
 

but the following code will process each line one by one:
for n in {1..file_length}; do head -$n /etc/hosts | tail -1 | your_command ; done

where "file_length" is the number of lines in your /etc/hosts file.
and "your_command" is what you want to do to the line.
leave out the pipe to "your_command" and it essentially echos the file one line at a time.

If there's a better way to do this without resorting to a real computer language, I'd like to know too.

Hope that helps.

You could use "getent" to retrieve values from certain administrative databases. (passwd, group, hosts, services, protocols, or networks)

Thanks jschiwal
 

Never met the "getent" critter before. While it's useful for this user's specific problem, what's a good way in general to pull a single line from a file. Piping through head and tail seems a bit of a kludge to me.

Cheers