Date: Tue, 18 Feb 2020 14:50:50 +0100
From: Joerg Schilling <joerg.schill...@fokus.fraunhofer.de>
Message-ID: <5e4bebba.XCR/ahv7oqvibm+7%joerg.schill...@fokus.fraunhofer.de>
| If you like to get the previous POSIX behavior, call:
|
| time -p some-command
|
| This is what POSIX did require in the past...
No, it didn't, the -p is needed only to get the POSIX specific
output format.
| When you do that, you of course cannot time functions or builtins.
Not directly, one can time a script that runs the function/builtin
and subtract the time for running an empty script, but that is kind
of complex. Why someone would want to time a builtin I'm not sure
(with the possible exception of elapsed time of wait)
| There however is a shell that has massive problems: "zsh".
|
| zsh cannot time functins or builtins at all and even more:
|
| time -p sleep 1
| zsh: command not found: -p
|
| as you see, the command line documentd by POSIX does not work.
But
time sleep 1
works in it just fine...
zsh $ time sleep 1
sleep 1 0.00s user 0.00s system 0% cpu 1.004 total
The output format isn't POSIX standard, but the data is there.
Further:
zsh $ \time -p sleep 1
real 1.00
user 0.00
sys 0.00
zsh $ command time -p sleep 1
real 1.00
user 0.00
sys 0.00
also both work, so it isn't quite as hopeless as it seems. Both of
those suppress the reserved word processing, and I guess I really
should have used
zsh $ \command time -p sleep 1
real 1.00
user 0.00
sys 0.00
just in case "command" has been turned into a reserved word as well
(since apparently that's possible, and entirely POSIX compatible).
kre
