Quickly watching configuration files in linux

Suppose you want to configuring something in Linux. For that you have to open configuration files in Linux via vi command editor. What if you want to know whatever changes you have made active. For that I just found a simple command on Cyberciti.biz website. Thought this may be useful for you guys.

#cat config_file_name.conf | sed '/ *#/d; /^ *$/d'

(grep will remove all comments and sed will remove all empty lines)