The time command lets you time programs to find out how much processor time they actually require. You might use this to compare two versions of a program to see if one runs faster than the other. You can run a program with:

time command-line

where command-line is a command line that invokes the program you want to time. time runs the program and displays:

• The total time the program took to execute, labeled real
• The total time spent in the user program, labeled user
• The central processor time spent performing system services for the user, labeled sys