Most important trick in ubuntu

Incremental Search(one of the best tricks on terminal)

To understand the beauty of incremental search.. lets simply dig in subject..
create and open .inputrc file in home directory..

$ > .inputrc
$ gedit .inputrc

and add following to it..

"\e[A": history-search-backward
"\e[B": history-search-forward
"\e[C": forward-char
"\e[D": backward-char 

Now exit the terminal and simply type "cd" and press up or down arrow key to search the history of cd command