Question

I know there are a lot of different threads already like this, but nothing I can find seems to explain well enough exactly what I’m trying to do.

Basically I want to have a shell script that just goes through a text file, line by line, and searches for the words “Error” or “Exception”. Whenever it comes across those words it would record the line number so I can later shoot the text file off in an email with the problem lines.

I’ve seen a lot of stuff that explains how to loop through a text file line by line, but I don’t understand how I can run a regular expression on that line, because I’m not sure exactly how to use regular expressions with a shell script and also what variable each line is being stored in…

If anybody can clarify these things for me I would really appreciate it.

Answer 1

There are numerous tools that automatically loop thru files. I would suggest a simple solution like:

 grep -inE 'error|exception' logfile > /tmp/logSearch.$$ 
 if [[ -s /tmp/logSearch.$$ ]] ;then
   mailx -s "errors in Log" < /tmp/logSearch.$$
 fi
 /bin/rm /tmp/logSearch.$$

use man grep to understand the options I’m supplying.

From `man bash

 -s file
True if file exists and has a size greater than zero. 

I hope this helps.