Terminal History

This tip will be useful for someone who is new to the Terminal environment. The Terminal keeps a history of old commands that you have used before, so if you used some command long ago and want to find it you can do a quick search.

To display the history of the Terminal just type history:

samer@ubuntu:~$ history

To start search just use Ctrl+R and it will display the following:

(reverse-i-search)`': <your-search-query>

where you can start typing you search query.

Hope its helpful ... Thanks,

Ref:
lifehacker