Command line is more powerful because you can do lot with them, you can tell your computer exactly what you want and get the appropriate answer. 

That is why most of us use the terminal at least once a day.  Today we will see another List of useful commands, i`m sure that most of you didn`t hear about them before.  Lets see . 

1- Run the last command as Root

sudo !! 

2- Save a file you edited in vim/vi without the needed permissions

:w ! sudo tee %

If you opened a file for edit and when saving you noticed that you forgot to open file as root, the command above is the solution. 

3- Runs previous command but replacing : “foo” by “bar”

^foo^bar

If you did run a long command and you noticed that you made a mistake, to correct the command you can replace only the mistake by the correct word without the need to run the whole command again. 

Another alternative to the above command is:

!!: gs/foo/bar

As opposed to ^foo^bar, which only replaces the first occurrence of foo, this one changes every occurrence

4- Short and elegant way to copy or backup a single file before you edit it. 

cp filename{,.bak}

5- mtr, better than traceroute and has ping combined

mtr unixmen.com

mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool. 

6- Empty a file without removing it

> file.txt

7- Execute command without saving it in the history

<space>command

8- Clear a terminal screen

ctrl-l

9- List of commands you use most often

history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head

10- Get your external IP address. 

curl ifconfig.me

This is all for today, enjoy