Recently I wrote an article about how to view live any log changes in the console, to expand that command, I decided to compile a list of sysadmin commands extreamly usefull.
A real time system usage of server resources, by default you will see CPU & RAM usage and which PID is using the highest resources.
This is one of the most important linux command, it shows the information about other commands. To begin with you can type "man man" and the result will be :
Using vmstat you can see the processes, memory, paging, block IO, traps, and cpu activity.
Extending a bit the functionality of vmstat, if you add -m it will display display memory utilization slabinfo .
Display the current processes working with unique ID.