Shell Programming and Scripting

Hi, so I have been trying to write a shell script to go through a log file and through that, generate another file with all the Valid IP addresses it finds. So there's the complication that there could be incomplete or invalid data which would disqualify it from making my "Valid IPs" file I need to generate.

So I already have working code/script which can check if a chunk of stuff with no spaces in it is one Valid IP or not. That seems to work fine.

Problem is, I don't know specifically what else do I need to do and/or code and how to use my function in conjunction with a log file and how to make things work together.

Though I have ways of reducing the data set of useless lines , (i.e. by calling grep), I'm not completely sure if that's best to do and how to best pass in the reduced data set where I can still traverse it and/or how to traverse it so that my function/script can work on Validating if each potential chunk is a real IP or not.
I am willing to edit this function to traverse several lines of potential chunks, but don't know how to traverse nor get each chunk within the lines.
Or what should I do?

For example, let's say log file has following format:

maryjane from 10.23.17.11
johnston4 from 20..70.81
mail server exception, port 3209
controller from 321.24.70.18
brady from 110.113.270.
carriemoon from 111.123.199.291
error type 209.134 handled
barkleyjohnson from 0.43.205.34
bishopqueen from 2.100.999.8
billyj from 71.253.82.114
firewall and security handler invoked Mar 15 05:24:33
freewill from 28.49.130.
marklouis from .111.250.230

Anyways, I don't know how to go about all this.
Code and suggestions would help and be appreciated

Thanks in advance.

If you have grep that supports -o and -w, this should do the trick:

Code:

IPD='(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9])'
grep -woE "$IPD\.$IPD\.$IPD\.$IPD" infile

Or using awk:

Code:

awk -v IPD='(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[1-9])' '{
 while(match($0,W IPD"\\."IPD"\\."IPD"\\."IPD W)) {
     print substr($0, RSTART+1, RLENGTH-2);
         $0=substr($0,RSTART+RLENGTH);
 }} ' W='[^[:digit:][:alpha:]_]' infile

Thanks, I'll definitely try that out later. It might be easier.
I actually did find out on my own how to do what I needed. Trivial, but cryptic to see sometimes.

If you want to get each string of numbers and dots from a file to pass to your function you could do something like this:

Code:

grep -oE "[.[:digit:]]*" infile | while read word
do
      your_function $word
done

or again if you don't have -o in your grep:

Code:

 sed 's/[^0-9.]/\
/g' infile | sed '/^$/d' | while read word
do
    your_function $word
done