How to interpret time command output?

The output of the time command consists of three main lines, each providing different timing information:

1. Real Time:

   • This line shows the total elapsed time from start to finish of the command.
   • Format: real XmYs (where X is minutes and Y is seconds).
   • Example: real 0m0.003s means the command took 0 minutes and 0.003 seconds to execute.

2. User Time:

   • This line indicates the amount of CPU time spent in user mode, which is the time the CPU spent executing the command itself.
   • Format: user XmYs.
   • Example: user 0m0.001s means the CPU spent 0.001 seconds executing the command in user mode.

3. System Time:

   • This line shows the amount of CPU time spent in kernel mode, which includes time spent on system calls and other kernel-level operations.
   • Format: sys XmYs.
   • Example: sys 0m0.001s means the CPU spent 0.001 seconds in kernel mode while executing the command.

By analyzing these three metrics, you can gain insights into the performance of the command, identify potential bottlenecks, and understand how system resources were utilized during execution.