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I'm trying to measure the execution time of a process that I call via the command line (i.e., I want to find out how long it takes to for the process to finish). Is there any command that I can add to the command calling the process that will achieve this?

9 Answers 9

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Add time before the command you want to measure. For example: time ls.

The output will look like:

real    0m0.606s
user    0m0.000s
sys     0m0.002s

Explanation on real, user and sys (from man time):

  • real: Elapsed real (wall clock) time used by the process, in seconds.
  • user: Total number of CPU-seconds that the process used directly (in user mode), in seconds.
  • sys: Total number of CPU-seconds used by the system on behalf of the process (in kernel mode), in seconds.
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    @ninjalj, can you provide more information on what the real, user, and sys times are that this command returns? Jul 17, 2011 at 20:22
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    @JacobVlijm This answer isn't that elaborate. :) You could edit in your comment and make it so.
    – muru
    Feb 13, 2015 at 16:43
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    Note that you may need sudo apt-get install time if you are using a shell where time is not a builtin.
    – poolie
    Oct 26, 2016 at 16:45
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    Note that this is the output from Bash's time builtin, but man time would be about an executable (like /usr/bin/time, from the time package), and its output would look different. Also in Bash, you can run help time for help with the builtin.
    – wjandrea
    Mar 25, 2019 at 21:08
  • Note that the process end does not mean all the work is finished. A copy may take additional minutes after the "time" returns for flushing system bufffers (therefor with unallocated sys time also).
    – ubfan1
    Jun 23, 2019 at 16:25
64

For a line-by-line delta measurement, try gnomon.

It is a command line utility, a bit like moreutils's ts, to prepend timestamp information to the standard output of another command. Useful for long-running processes where you'd like a historical record of what's taking so long.

Piping anything to gnomon will prepend a timestamp to each line, indicating how long that line was the last line in the buffer--that is, how long it took the next line to appear. By default, gnomon will display the seconds elapsed between each line, but that is configurable.

gnomon demo

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    This is pretty slick. Sep 8, 2016 at 21:53
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    (typo in link, fortunately URL ok). You can install it with sudo npm i gnomon -g if you have npm. Not sure how well it does against "progress" lines using '\r' (staying on the same line): in that case I'd like it counting it all as one long line, not separate ones. Jun 14, 2017 at 21:42
  • so we pipe it to gnomon ! thats it ? May 15, 2018 at 9:44
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    It is deprecated now, is there any similar alternative now? May 23, 2022 at 14:46
32

You can use time:

time ls -R
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date +"%T" && cp -r ./file  /destination/folder/here && date +"%T"

Running this command in the terminal will give you the total time for coping a file

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    This will give you the start time and end time, not the duration.
    – wjandrea
    Mar 25, 2019 at 19:31
  • This is a good answer, under some circumstances. For example, the following find command -- without the 2>/dev/null redirect -- gives copious Permission denied messages. However, adding 2>/dev/null to that command breaks the time portion of that command. The following provides a good compromise: START="$(date +"%s")" && find 2>/dev/null / -path /mnt -prune -o -name "*libname-server-2.a*" -print; END="$(date +"%s")"; TIME="$((END - START))"; printf 'find command took %s sec\n' "$TIME", giving (e.g.) /usr/lib/libname-server-2.a find command took 3 sec as the sole output. May 22, 2019 at 3:45
  • An addendum to my comment: of course, you can simply run time sudo find / -path /mnt -prune -o -name "*libname-server-2.a*" -print (i.e., as sudo) -- avoiding those numerous Permission denied warnings. May 22, 2019 at 16:04
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Occasionally I find myself needing a stopwatch to count how long it takes for an action like my app booting, in which case many of the solutions here are not useful.

For this I like to use sw.

sw

Install

wget -q -O - http://git.io/sinister | sh -s -- -u https://raw.githubusercontent.com/coryfklein/sw/master/sw

Usage

sw
 - start a stopwatch from 0, save start time in ~/.sw
sw [-r|--resume]
 - start a stopwatch from the last saved start time (or current time if no last saved start time exists)
 - "-r" stands for --resume
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time -v command

-v gives more information

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    -v: command not found
    – Gqqnbig
    Mar 17, 2021 at 8:26
  • @Gqqnbig were you using this command on Mac OS? If yes, you can brew install gnu-time and use the command gtime instead of time. Sep 22, 2021 at 14:30
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    If you use bash as your shell, it will use it's inbuild time function. To use the time program you may use /usr/bin/time -v COMMAND or command time -v COMMAND. :) Nov 15, 2022 at 23:50
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In zsh, the time command's output is slightly different.

To interpret the output:

time sleep 10
sleep 10  0.00s user 0.00s system 0% cpu 10.011 total

The last number gives the total time as though it were recorded with a real life stopwatch (what you want 99% of the time). The other values are explained here.

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In Nushell, the command is timeit instead of time.

> timeit java -jar benchmark.jar concurrency
[program output]
3min 42sec 994ms 803µs 978ns
-2
  1. Open bashrc file

    gedit ~\.bashrc
    
  2. Find the following text:

    if [ "$color_prompt" = yes ]; then
        PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\] :\[\033[01;34m\]\w\[\033[00m\]\$ ' 
    
  3. And replace with:

    if [ "$color_prompt" = yes ]; then
        PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u\[\033[00m\] [\d|\t]:\[\033[01;34m\]\w\[\033[00m\]\$ ' 
    
  4. Restart terminal to check.

Sample output in terminal

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    This will show the time. It will neither build the difference to the last command, nor will it account for waiting to type and hit ENTER or typing the command. Nov 15, 2022 at 23:54

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