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I imagine time A | B would only measure the time taken to run A (since the argument to time is A). What's the solution ?

boredaf
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2 Answers2

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Depends on the shell. e.g. Bash has a keyword time that times the whole pipeline. An external implementation of time would only time A in your example. A workaround might be to explicitly run an extra shell:

time sh -c "A | B"
Gilles 'SO- stop being evil'
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ilkkachu
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  • Technically `time` is not a builtin, but a keyword (in bash, and in ksh and zsh which have the same feature). It has to be so that `time` applies to the following compound command and not just to a simple command. – Gilles 'SO- stop being evil' Jul 11 '17 at 23:42
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You could also use a subshell, e.g.

 time ( A | B )

at least when time is the bash builtin (but then a subshell is useless). If you want to use the time(1) command (see this) you'll better explicitly run some sh -c like answered by iikkachu

Basile Starynkevitch
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