Here is another set of commands that has some useful system style information that you execute from the terminal or shell.
date – Shows the current date and time on the system.
cal – Display the calander
uptime – How long has the system been running.
whoami – Shows the currently logged in user.
free – displays the free memory on the system.
whereis app – replace the word app with the name of the application to find where that application is installed.
df -h – disk space usage