I am using this command to search the Internet for open ports on port 80 with nmap.
sudo nmap -sS -iR 0 -p 80 -oG nmap.grepable
Then I use this command in another terminal tab to view the updating file. This will be updated every two seconds with new file content.
watch cat nmap.grepable
This is a good way to monitor files for any changes.
This is another good way. This command will constantly monitor the /var/log/dmesg file for any new kernel messages.
watch tail -n 10 /var/log/dmesg
This command will watch for new kernel messages.
watch tail /var/log/kern.log
The watch command is a very useful tool to run in a spare xterm to monitor your logfiles. Give these tricks a try and see how useful they really are.