UNIX for Dummies Questions & Answers

hi

im completely new at unix so dont hate me for asking what is probably the easiest question ever.

below is an extract of some data im processing. the first column is like a counter while the second is an ip address. i need to be able to output the ip address based on which has the largest counter number. as you can see the data is already sorted by the size of the counter. hence the output would be 66.249.66.103.

Code:

     65 138.130.16.56
     67 207.46.98.38
     79 65.214.44.112
     82 66.151.181.10
     94 209.191.65.248
     96 207.46.98.37
     97 207.46.98.39
    104 207.46.98.40
    178 66.249.65.167
    457 66.249.66.103

please help me do this, i have no idea how to do it. ALSO...please keep the answer simple otherwise i will just get lost
thanks

To print the last line of a file, use the "tail" command.

Code:

tail -n 1 filename

Conventionally, we would probably sort so that the top result is at the top, and use "head".

Don't worry about this part, I'm just giving you hints in case you want to develop your skills in the future.

Code:

sort -rn filename | head -n 1

If you want to split off the counter and just see the IP address, you can post-process the output from tail (or head, or any command) with a command like "cut" or "awk" or ... there's a myriad variations. I'll use awk here because it conveniently handles the space-padded format you are using (cut would have a problem with that);

Code:

tail -n 1 filename | awk '{print $2}'

awk is a full-blown scripting language so you could do all of this in awk, but I guess you are overwhelmed already.

thanks a lot. that was a big help. yeah i knew that awk could do it all, but i prefer to work through it step by step using the simple commands.

btw this is not related to my previous question, but when setting out unix code are there any ever new lines between pipelines? coz im writing a script and it has 8 pipelines at the moment which tends to get a bit messy. ie what is the correct setting out for longer unix code.

The shell allows you to split pipelines across multiple lines without any continuation character.

Code:

grep fnord /tmp/file |
nl |
sed -e 's/foo/bar/' |
cat -A |
whatever ...

In the general case, it's probably better to post a new question under a different topic title, because many readers only look at the topic titles and only read the ones they know the answer to (or find interesting, or don't know the answer to, depending on who they are and what they do).

great. thanks a lot for ur help