10 great and powerful Linux commands you may need to know
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 http://www.unixmen.com