How to get execution time of a script effectively?

Question

I would like to display the completion time of a script.

What I currently do is -

#!/bin/bash
date  ## echo the date at start
# the script contents
date  ## echo the date at end

This just show's the time of start and end of the script. Would it be possible to display a fine grained output like processor time/ io time , etc?

Answer 1

just use time when you call the script.

time yourscript.sh

Answer 2

Just call time or times without arguments upon exiting your script.

times is the POSIX way, but time is supported by ksh, bash and zsh but with different information provided.

Also note that all of bash, ksh and zsh have a $SECONDS special variable that counts the number of seconds since the shell was started. In both zsh and ksh93, that variable can also be made floating point (with typeset -F SECONDS) to get more precision. This is only wall clock time, not CPU time.

Answer 3

If time isn't an option,

start=`date +%s`
stuff
end=`date +%s`

runtime=$((end-start))