Linux Tip #1: Live monitoring with tail

This is something every Linux admin or Linux superuser probably already knows and uses everyday.

The “tail -f” command monitors a file and tracks any changes to it. As changes are made to the monitored file the “tail” command will print them on screen. Live monitoring basically…..

tail -f [log file]

Sample output;

[root@keke ~]# tail -f /var/log/messages

Mar 16 11:06:39 keke dhcpd: DHCPREQUEST for 172.28.6.233 from 00:1b:78:d2:bc:0e via eth0
Mar 16 11:06:39 keke dhcpd: DHCPACK on 172.28.6.233 to 00:1b:78:d2:bc:0e via eth0
Mar 16 11:06:39 abubu dhclient: DHCPREQUEST on eth0 to 172.28.1.41 port 67
Mar 16 11:06:39 abubu dhclient: DHCPACK from 172.28.1.41
Mar 16 11:06:39 abubu dhclient: bound to 172.28.6.233 -- renewal in 33912 seconds.
Mar 16 11:06:46 keke dhcpd: DHCPDISCOVER from 00:14:5e:ce:66:14 via eth0
Mar 16 11:06:46 keke dhcpd: DHCPOFFER on 172.28.4.123 to 00:14:5e:ce:66:14 via eth0
Mar 16 11:06:54 keke dhcpd: DHCPREQUEST for 172.28.4.123 (172.28.1.41) from 00:14:5e:ce:66:14 via eth0
Mar 16 11:06:54 keke dhcpd: DHCPACK on 172.28.4.123 to 00:14:5e:ce:66:14 via eth0
Mar 16 11:06:54 keke atftpd[21175]: Serving /tftpboot/pxelinux.0 to 172.28.4.123:2070
Mar 16 11:06:54 keke atftpd[21175]: Serving /tftpboot/pxelinux.0 to 172.28.4.123:2071
Mar 16 11:06:54 keke atftpd[21175]: Serving /tftpboot/pxelinux.cfg/01-00-14-5e-ce-66-14 to 172.28.4.123:57089
Mar 16 11:06:54 keke atftpd[21175]: Serving /tftpboot/pxelinux.cfg/AC1C047B to 172.28.4.123:57090