Server Load - Top Command

Top command – Linux

Top - command produces a frequently-updated list of processes. By default, the processes are ordered by percentage of CPU usage, with only the "top" CPU consumers shown. The top command shows how much processing power and memory are being used, as well as other information about the running processes.

Sample Output is Given above

The information in the screenshot
uptime – Server Uptime
Users – Number of user Login
Load aversage – Server Load Information
  eg: load average: 0.41, 0.50, 1.256
during the last minute, the CPU was overloaded by 41% (1 CPU with 0.41 runnable processes, so that 0.73 processes were waiting for a turn) 
during the last 5 minutes, the CPU was underloaded 50% (no processes were waiting for a turn) 
during the last 15 minutes, the CPU was overloaded 256% (1 CPU with 1.25 runnable processes, so that 6.98 processes were waiting for a turn) 
Options

Some options to top are listed below.

 -d: Delay time interval as: -d ss.tt (seconds. tenths)
  Specifies the delay between screen updates
  
 eg) top -d 04.59

 -u: Monitor by user as: -u somebody
  Monitor only processes with an effective UID or user name matching
  That given.
 c: RUSER -- Real User Name. The real user name of the task's owner.
eg) top -u sahab

Use the -n flag to limit the number of iterations: 
  top -n 1