Re: time command with shell builtins

[Mikael Magnusson <mikachu@xxxxxxxxx>]

On 1/23/23, Dominik Vogt <dominik.vogt@xxxxxx> wrote:
> On Mon, Jan 23, 2023 at 02:42:05PM +0100, Roman Perepelitsa wrote:
>> On Mon, Jan 23, 2023 at 2:40 PM Dominik Vogt <dominik.vogt@xxxxxx> wrote:
>> >
>> > Is it possible to get timing statistics of shell builtins too?
>> > Timing "echo" isn't very interesting, but timing loop constructs
>> > would be:
>> >
>> >   $ time while foo; do bar done
>>
>> This:
>>
>>     % time ( while foo; do bar; done )
>
> That wasn't really the question.  Of course I can time a loop by
> writing a different command, or by putting it in a pipe or file.
>
>   $ time echo foo | true
>
> I just want to get timing statistics of loops either explicitly by
> prepending "time" or implicitly with REPORTTIME.

As Bart already mentioned, the answer to your question is "no", but
you can avoid some downsides of the subshell (eg, if your loop has
side effects that are relevant to the rest of the script etc), by
using SECONDS:
% () { typeset -F4 SECONDS=0; sleep 1; () { typeset -F3 SECONDS=0;
sleep 0.43; echo $SECONDS }; sleep 1; echo $SECONDS }
0.431
2.4329
(the downside here is obviously that it doesn't split out cpu/system
time for you, only elapsed time).

-- 
Mikael Magnusson