What do the terms `real`, `user`, and `sys` mean in the output of the `time` command? How can you use these values to understand the performance of a process?
real is the total time it took to run the processes from start to finish, including the time that the CPU spent doing other tasks. user time is the number of seconds that the CPU has spent running the program's own code. The system time is how much time the kernel spends doing the process's work. By subtracting the user and system time from real time, one can get a general idea of how long a process spends waiting for system and external resources.