[CentOS] time foo

[Gordon Messmer]

On 12/01/2017 08:49 AM, hw wrote:
> # time foo
> real    43m39.841s
> user    15m31.109s
> sys     0m44.136s
>
>
> Almost 30 minutes have disappeared, but it actually took about that long,
> so what happened? 


I may misunderstand your question, but

"time" is provided by the bash shell.  It may be provided by a command 
if you are using a different shell.  When the command following the 
"time" keyword completes, bash will print the amount of elapsed time 
(the amount of time that passed between the command's start and its 
exit), the amount of time the command was using the CPU and not in a 
sleep state, and the amount of time the kernel was using the CPU to 
service requests from the command.

So your "foo" application was in a sleep state for around 30 minutes of 
the 44 minutes that passed between when you started it and when it finished.