multitail; a tail replacement

Often times, tail provides enough log viewing experience for diagnosis, analysis, etc. However, its functionality is still limited and unable to provide additional features such as multiple logs viewing, colorize output, column support, and so on.

This, however, is possible using another package – multitail. Multitail provides the support for logs coloring, columns, multiple logs, logs merging, interval command execution, and so on.

Install multitail in Ubuntu

$ sudo apt-get update
$ sudo apt-get install multitail

Example #1: View 2 files simultenuosly

Supposed we want to monitor 2 Nginx sites’ access logs, here’s the command

$ multitail /var/log/nginx/site1.access.log /var/log/nginx/site2.access.log

Example #2: View 2 files merged as 1, with different colors

Let’s get more visuals. Now we want to monitor access logs and error logs as a single file, and each file is represented in different colors so we can differentiate them in our diagnostic.

$ multitail -ci green /var/log/nginx/site1.access.log \
-ci red -I /var/log/nginx/site1.error.log

Example #3: View 4 logs merged as 2 pair, in 2 columns

So you need to see how one site’s error relates to other sites. Now we want to monitor access & error logs of 2 sites in 2 columns. Each column represents a single site with green color for the access log and red color for the error log.

$ multitail -s 2 \
-ci green /var/log/nginx/site1.access.log -ci red -I /var/log/nginx/site1.error.log \
-ci green /var/log/nginx/site2.access.log -ci red -I /var/log/nginx/site2.error.log

Get creative

There are a lot of possibilities you can explore depending on your use cases. For more information regarding multitail, you can refer to the following sites.

• https://www.my-tiny.net/L10-mtail.htm
• https://arkit.co.in/multitail-command-to-view-multiple-logs-in-single-terminal/