Command line essentials


installs and uninstalls software on Ubuntu/Debian systems. For example:

sudo apt install firefox

sudo apt remove firefox

apt list

sudo apt-get update

´‘sudo apt-get update‘‘ downloads the package list from the repositories and updates them to get information about the newest packages and their dependencies.


Will show a complete overview concerning a systems hardware:


will print info about the cpu type onto the shell

sudo lshw –short

will print the information onto the shell

sudo lshw -html >hw.html

will write the information in a html document

sudo lshw -xml >hw.xml

will write the information in an xml document


free -m

Will show how the memory is used


Note that this shell program is not always installed by default, if not installed type "sudo apt install tree".


$ tree

$ tree -d

$ tree -l number

-d will show only the directories, -l number will provide the depth, ie.: $ tree -l 3 will show the structure down to the 3rd level.



Will show: the current time, how long the system has been running, the number of users currently logged on, the system load avereages for the past 1, 5, 15 minutes


Will tell if an intersite (ping or a local system (ping -c 4 is available


To login via secure shell on a remote computer:

ssh user@

to login as user on the computer with IP-adress