multitail

MultiTail is an open source ncurses utility that can be used to display multiple logfiles to standard output in a single window or a single shell that shows last few lines of logfiles in a real-time like tail command which split console into more subwindows (much like screen command). It also supports color highlighting, filtering, adding and deleting windows and much more.

Features

Multiple input sources.
Color display using Regular Expression in the case of important informations.
Line filtering.
Interactive Menus for deleting and adding shells.

6. How to Merge/View Two Files in Different Color

Merge 2 logfiles in one window, but give different color to each logfile so that you can easily understand what lines are for what logfile.

[root@localhost ~]# multitail -ci green /var/log/yum.log -ci yellow -I /var/log/mysqld.log

tecmint.com/view-multiple-files-in-linux/

Examples

See http://www.vanheusden.com/multitail/examples.html for more and other examples.
multitail /var/log/apache/access_log logfile -i -filestartingwithdatsh
This creates three windows. One with the contents of /var/log/apache/access_log, one with the contents of logfile and so on.
multitail -R 2 -l dqnetstat -tdq
This runs netstat every 2 seconds and then shows what has changed since the previous run. That way one can see new connections being made and closed connections fading away.
multitail logfile -l dqping 192.168.1.3dq
This creates two windows. One with the contents of logfile, one with with the output of ‘ping 192.168.1.3’.
multitail /var/log/apache/access_log -I /var/log/apache/error_log
This creates one window with the contents of /var/log/apache/access_log merged with the contents of /var/log/apache/error_log.
multitail -M 0 /var/log/apache/access_log -I /var/log/apache/error_log
Same as previous example. This example will store all logged entries in a buffer so that you can later on browse through them (by pressing ‘ b ‘).

source: vanheusden.com/multitail/

Instll multitail : www.tecmint.com/view-multiple-files-in-linux/