$top

-Shows live processes currently running
-Only shows processes for a certain period of time (Like a drawback)
-The $ps command fails to show trend of processes that are being swapped in and out of memory; thus $top command

First Line:

Shows general system information
-Current time
-How long the system has been up
-The number of users logged in
-The load average

*more about the load average:
The load average is displayed in three different time marks:

• 1-minute
• 5-minute
• 15-minute

It's not uncommon for the 1 minute mark to be high, but if the 15 minute mark is high then system is in trouble