Master Real-Time Log Monitoring on Linux with tail, multitail, lnav & less

1. tail Command – Monitor Logs in Real Time

As mentioned, tail is the most common way to display logs in real time. It has two variants:

Using -f option

<code>$ sudo tail -f /var/log/apache2/access.log</code>

Using tailf (built‑in -f)

<code>$ sudo tailf /var/log/apache2/access.log</code>

For rotated logs, use

-F

to follow new files:

<code>$ sudo tail -F /var/log/apache2/access.log</code>

To view only the last two lines in real‑time, combine

-n

and

-f

:

<code>$ sudo tail -n2 -f /var/log/apache2/access.log</code>

2. Multitail Command – Monitor Multiple Log Files in Real Time

Multitail can monitor several logs simultaneously and allows scrolling.

Install Multitail:

<code>$ sudo apt install multitail   [On Debian &amp; Ubuntu]
$ sudo yum install multitail   [On RedHat &amp; CentOS]
$ sudo dnf install multitail   [On Fedora 22+ version]</code>

Example to display two logs:

<code>$ sudo multitail /var/log/apache2/access.log /var/log/apache2/error.log</code>

3. lnav Command – Monitor Multiple Log Files in Real Time

lnav is another tool for real‑time multi‑file monitoring.

Install lnav:

<code>$ sudo apt install lnav   [On Debian &amp; Ubuntu]
$ sudo yum install lnav   [On RedHat &amp; CentOS]
$ sudo dnf install lnav   [On Fedora 22+ version]</code>

Example usage:

<code>$ sudo lnav /var/log/apache2/access.log /var/log/apache2/error.log</code>

4. less Command – Display Real Time Output of Log Files

You can also use

less

and press Shift+F (or start with

+F

) to follow a file:

<code>sudo less +F /var/log/apache2/access.log</code>

Additional articles on log monitoring and management are listed:

Manage Files Effectively using head, tail and cat Commands in Linux

How to Setup and Manage Log Rotation Using Logrotate in Linux

Petiti – An Open Source Log Analysis Tool for Linux SysAdmins

How to Query Audit Logs Using ‘ausearch’ Tool on CentOS/RHEL

Manage Log Messages Under Systemd Using Journalctl {Comprehensive Guide}