Troubleshooting CentOS

Using grep

Now let's consider the need to search the server's log files for specific keywords.

In this situation, you would use the command known as grep, which also becomes a very helpful technique to learn when you would like to perform an advanced string-based search of almost any file on your server.

Let's say you wanted to search for a specific e-mail address in the mail log file. To do this, you would use grep in the following way:

# grep "[e-mail]" /var/log/maillog

Taking this one step further, grep can also be used to search in a recursive pattern across one or more files at the same time.

For example, in order to search the log file directory for an IP address (XXX.XXX.XXX.XXX), you would use the grep command in combination with the ...