Hot answers tagged time
The structure of a pipeline doesn't allow time in the middle, only at the start of the pipeline. Also, time is a "shell keyword", as shown by type time. But nothing forbids the use of compound commands (and time each): time comm1 | ( time comm2 ) So, you could workaround using a sub-shell, like this: echo "12" | ( time python3 -c "a=input("");print(a)" ...
There is two types of time commands. One is shell built-in, belongs to bash. That's the one you see in your first example. Second one , is /usr/bin/time, that's the second one you saw. As for why it's different output, it's because you cannot pipe output to shell builtins. More on that here
Using last you can find this information. The following may be useful: last <username> | less It will return something like this: benlavery@Talantinc:bin $>last benlavery | less benlavery ttys005 Mon Aug 31 09:58 still logged in benlavery ttys005 fe80::105e:6b27:29ff:d967%en0 Mon Aug 31 09:14 - 09:36 (00:22) benlavery ...
If you like to time commands for performance reasons, I recommend not to use /usr/bin/time but either ptime(1) if this available on your platform - ptime gives a nanosecond resolution - or to use a recent Bourne Shell, as the Bourne Shell allows to automatically time all foreground commands (including shell builtins) with a microsecond resolution on all ...
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