This bash one-liner will let you watch the tail end of a log file in real time.
I find myself keeping an eye on the Apache log when testing Linux deployments. This helps me see what the clients are requesting, whether the preseed file was fetched, etc. After writing this tip, I had this epiphany that this could be used for any log file. Just swap out /var/log/apache2/access.log
with your file of choice.