Get program execution time in the shell

Question

I want to execute something in a linux shell under a few different conditions  and be able to output the execution time of each execution   I know I could write a perl or python script that would do this  but is there a way I can do it in the shell   which happens to be bash

User · Answer

You can get much more detailed information than the bash built-in time (which Robert Gamble mentions) using time(1). Normally this is /usr/bin/time.

^{Editor's note:
To ensure that you're invoking the external utility time rather than your shell's time keyword, invoke it as /usr/bin/time.

time is a POSIX-mandated utility, but the only option it is required to support is -p.

Specific platforms implement specific, nonstandard extensions: -v works with GNU's time utility, as demonstrated below (the question is tagged linux); the BSD/macOS implementation uses -l to produce similar output - see man 1 time.}

Example of verbose output:

$ /usr/bin/time -v sleep 1
       Command being timed: "sleep 1"
       User time (seconds): 0.00
       System time (seconds): 0.00
       Percent of CPU this job got: 1%
       Elapsed (wall clock) time (h:mm:ss or m:ss): 0:01.05
       Average shared text size (kbytes): 0
       Average unshared data size (kbytes): 0
       Average stack size (kbytes): 0
       Average total size (kbytes): 0
       Maximum resident set size (kbytes): 0
       Average resident set size (kbytes): 0
       Major (requiring I/O) page faults: 0
       Minor (reclaiming a frame) page faults: 210
       Voluntary context switches: 2
       Involuntary context switches: 1
       Swaps: 0
       File system inputs: 0
       File system outputs: 0
       Socket messages sent: 0
       Socket messages received: 0
       Signals delivered: 0
       Page size (bytes): 4096
       Exit status: 0

User · Answer

For a line-by-line delta measurement  try gnomon      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    You can also use the --high and or --medium options to specify a length threshold in seconds  over which gnomon will highlight the timestamp in red or yellow  And you can do a few other things  too

User · Answer

Use the built-in time keyword      help time  time  time  -p  PIPELINE     Execute PIPELINE and print a summary of the real time  user CPU time      and system CPU time spent executing PIPELINE when it terminates      The return status is the return status of PIPELINE   The  -p  option     prints the timing summary in a slightly different format   This uses     the value of the TIMEFORMAT variable as the output format    Example     time sleep 2    real    0m2 009s user    0m0 000s sys     0m0 004s

User · Answer

The way is     gt  g   -lpthread perform c -o per    gt  time   per   output is     real    0m0 014s user    0m0 010s sys     0m0 002s

User · Answer

The way is     gt  g   -lpthread perform c -o per    gt  time   per   output is     real    0m0 014s user    0m0 010s sys     0m0 002s

User · Answer

one possibly simple method   that may not meet different users needs   is the use of shell PROMPT it is a simple solution that can be useful in some cases  You can use the bash prompting feature as in the example below   export PS1    t  u  h       The above command will result in changing the shell prompt to     HH MM SS username hostname     Each time you run a command  or hit enter  returning back to the shell prompt  the prompt will display current time   notes  1  beware that if you waited for sometime before you type your next command  then this time need to be considered  i e the time displayed in the shell prompt is the timestamp when the shell prompt was displayed  not when you enter command  some users choose to hit Enter key to get a new prompt with a new timestamp before they are ready for the next command  2  There are other available options and modifiers that can be used to change the bash prompt  refer to   man bash   for more details

User · Answer

If you intend to use the times later to compute with  learn how to use the -f option of  usr bin time to output code that saves times   Here s some code I used recently to get and sort the execution times of a whole classful of students  programs   fmt  run   date      date    user     who   test     test   host      hostname    times     user    U  system    S  elapsed    e       usr bin time -f   fmt  -o  timefile command args      I later concatenated all the  timefile files and pipe the output into a Lua interpreter   You can do the same with Python or bash or whatever your favorite syntax is   I love this technique

User · Answer

If you only need precision to the second  you can use the builtin  SECONDS variable  which counts the number of seconds that the shell has been running   while true  do     start  SECONDS     some long running command     duration     SECONDS - start        echo  This run took  duration seconds      if some condition  then break  fi done

User · Answer

Should you want more precision  use  N with date  and use bc for the diff  because       only handles integers    Here s how to do it   start   date   s  N    do some stuff here dur   echo    date   s  N  -  start    bc   printf  Execution time    6f seconds   dur   Example   start   date   s  N       sleep 0 1s      dur   echo    date   s  N  -  start    bc       printf  Execution time    6f seconds n   dur   Result   Execution time  0 104623 seconds

User · Answer

You can use time and subshell      time     for    i 1  i lt 10000  i       do     echo 1  gt  dev null   done     Or in same shell      time     for    i 1  i lt 10000  i       do     echo 1  gt  dev null   done

User · Answer

If you intend to use the times later to compute with  learn how to use the -f option of  usr bin time to output code that saves times   Here s some code I used recently to get and sort the execution times of a whole classful of students  programs   fmt  run   date      date    user     who   test     test   host      hostname    times     user    U  system    S  elapsed    e       usr bin time -f   fmt  -o  timefile command args      I later concatenated all the  timefile files and pipe the output into a Lua interpreter   You can do the same with Python or bash or whatever your favorite syntax is   I love this technique

User · Answer

Use the built-in time keyword      help time  time  time  -p  PIPELINE     Execute PIPELINE and print a summary of the real time  user CPU time      and system CPU time spent executing PIPELINE when it terminates      The return status is the return status of PIPELINE   The  -p  option     prints the timing summary in a slightly different format   This uses     the value of the TIMEFORMAT variable as the output format    Example     time sleep 2    real    0m2 009s user    0m0 000s sys     0m0 004s

User · Answer

Use the built-in time keyword      help time  time  time  -p  PIPELINE     Execute PIPELINE and print a summary of the real time  user CPU time      and system CPU time spent executing PIPELINE when it terminates      The return status is the return status of PIPELINE   The  -p  option     prints the timing summary in a slightly different format   This uses     the value of the TIMEFORMAT variable as the output format    Example     time sleep 2    real    0m2 009s user    0m0 000s sys     0m0 004s

User · Answer

one possibly simple method   that may not meet different users needs   is the use of shell PROMPT it is a simple solution that can be useful in some cases  You can use the bash prompting feature as in the example below   export PS1    t  u  h       The above command will result in changing the shell prompt to     HH MM SS username hostname     Each time you run a command  or hit enter  returning back to the shell prompt  the prompt will display current time   notes  1  beware that if you waited for sometime before you type your next command  then this time need to be considered  i e the time displayed in the shell prompt is the timestamp when the shell prompt was displayed  not when you enter command  some users choose to hit Enter key to get a new prompt with a new timestamp before they are ready for the next command  2  There are other available options and modifiers that can be used to change the bash prompt  refer to   man bash   for more details

User · Answer

bin bash START   date   s    do something   start your script work here ls -R  etc  gt   tmp x rm -f  tmp x   your logic ends here END   date   s  DIFF      END -  START    echo  It took  DIFF seconds

User · Answer

If you intend to use the times later to compute with  learn how to use the -f option of  usr bin time to output code that saves times   Here s some code I used recently to get and sort the execution times of a whole classful of students  programs   fmt  run   date      date    user     who   test     test   host      hostname    times     user    U  system    S  elapsed    e       usr bin time -f   fmt  -o  timefile command args      I later concatenated all the  timefile files and pipe the output into a Lua interpreter   You can do the same with Python or bash or whatever your favorite syntax is   I love this technique

User · Answer

bin bash START   date   s    do something   start your script work here ls -R  etc  gt   tmp x rm -f  tmp x   your logic ends here END   date   s  DIFF      END -  START    echo  It took  DIFF seconds

User · Answer

You can get much more detailed information than the bash built-in time (which Robert Gamble mentions) using time(1). Normally this is /usr/bin/time.

^{Editor's note:
To ensure that you're invoking the external utility time rather than your shell's time keyword, invoke it as /usr/bin/time.

time is a POSIX-mandated utility, but the only option it is required to support is -p.

Specific platforms implement specific, nonstandard extensions: -v works with GNU's time utility, as demonstrated below (the question is tagged linux); the BSD/macOS implementation uses -l to produce similar output - see man 1 time.}

Example of verbose output:

$ /usr/bin/time -v sleep 1
       Command being timed: "sleep 1"
       User time (seconds): 0.00
       System time (seconds): 0.00
       Percent of CPU this job got: 1%
       Elapsed (wall clock) time (h:mm:ss or m:ss): 0:01.05
       Average shared text size (kbytes): 0
       Average unshared data size (kbytes): 0
       Average stack size (kbytes): 0
       Average total size (kbytes): 0
       Maximum resident set size (kbytes): 0
       Average resident set size (kbytes): 0
       Major (requiring I/O) page faults: 0
       Minor (reclaiming a frame) page faults: 210
       Voluntary context switches: 2
       Involuntary context switches: 1
       Swaps: 0
       File system inputs: 0
       File system outputs: 0
       Socket messages sent: 0
       Socket messages received: 0
       Signals delivered: 0
       Page size (bytes): 4096
       Exit status: 0

User · Answer

If you intend to use the times later to compute with  learn how to use the -f option of  usr bin time to output code that saves times   Here s some code I used recently to get and sort the execution times of a whole classful of students  programs   fmt  run   date      date    user     who   test     test   host      hostname    times     user    U  system    S  elapsed    e       usr bin time -f   fmt  -o  timefile command args      I later concatenated all the  timefile files and pipe the output into a Lua interpreter   You can do the same with Python or bash or whatever your favorite syntax is   I love this technique

User · Answer

Should you want more precision  use  N with date  and use bc for the diff  because       only handles integers    Here s how to do it   start   date   s  N    do some stuff here dur   echo    date   s  N  -  start    bc   printf  Execution time    6f seconds   dur   Example   start   date   s  N       sleep 0 1s      dur   echo    date   s  N  -  start    bc       printf  Execution time    6f seconds n   dur   Result   Execution time  0 104623 seconds

User · Answer

If you only need precision to the second  you can use the builtin  SECONDS variable  which counts the number of seconds that the shell has been running   while true  do     start  SECONDS     some long running command     duration     SECONDS - start        echo  This run took  duration seconds      if some condition  then break  fi done

User · Answer

You can use time and subshell      time     for    i 1  i lt 10000  i       do     echo 1  gt  dev null   done     Or in same shell      time     for    i 1  i lt 10000  i       do     echo 1  gt  dev null   done

User · Answer

You can get much more detailed information than the bash built-in time (which Robert Gamble mentions) using time(1). Normally this is /usr/bin/time.

^{Editor's note:
To ensure that you're invoking the external utility time rather than your shell's time keyword, invoke it as /usr/bin/time.

time is a POSIX-mandated utility, but the only option it is required to support is -p.

Specific platforms implement specific, nonstandard extensions: -v works with GNU's time utility, as demonstrated below (the question is tagged linux); the BSD/macOS implementation uses -l to produce similar output - see man 1 time.}

Example of verbose output:

$ /usr/bin/time -v sleep 1
       Command being timed: "sleep 1"
       User time (seconds): 0.00
       System time (seconds): 0.00
       Percent of CPU this job got: 1%
       Elapsed (wall clock) time (h:mm:ss or m:ss): 0:01.05
       Average shared text size (kbytes): 0
       Average unshared data size (kbytes): 0
       Average stack size (kbytes): 0
       Average total size (kbytes): 0
       Maximum resident set size (kbytes): 0
       Average resident set size (kbytes): 0
       Major (requiring I/O) page faults: 0
       Minor (reclaiming a frame) page faults: 210
       Voluntary context switches: 2
       Involuntary context switches: 1
       Swaps: 0
       File system inputs: 0
       File system outputs: 0
       Socket messages sent: 0
       Socket messages received: 0
       Signals delivered: 0
       Page size (bytes): 4096
       Exit status: 0

User · Answer

Use the built-in time keyword      help time  time  time  -p  PIPELINE     Execute PIPELINE and print a summary of the real time  user CPU time      and system CPU time spent executing PIPELINE when it terminates      The return status is the return status of PIPELINE   The  -p  option     prints the timing summary in a slightly different format   This uses     the value of the TIMEFORMAT variable as the output format    Example     time sleep 2    real    0m2 009s user    0m0 000s sys     0m0 004s

User · Answer

For a line-by-line delta measurement  try gnomon      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    You can also use the --high and or --medium options to specify a length threshold in seconds  over which gnomon will highlight the timestamp in red or yellow  And you can do a few other things  too

User · Answer

You can get much more detailed information than the bash built-in time (which Robert Gamble mentions) using time(1). Normally this is /usr/bin/time.

^{Editor's note:
To ensure that you're invoking the external utility time rather than your shell's time keyword, invoke it as /usr/bin/time.

time is a POSIX-mandated utility, but the only option it is required to support is -p.

Specific platforms implement specific, nonstandard extensions: -v works with GNU's time utility, as demonstrated below (the question is tagged linux); the BSD/macOS implementation uses -l to produce similar output - see man 1 time.}

Example of verbose output:

$ /usr/bin/time -v sleep 1
       Command being timed: "sleep 1"
       User time (seconds): 0.00
       System time (seconds): 0.00
       Percent of CPU this job got: 1%
       Elapsed (wall clock) time (h:mm:ss or m:ss): 0:01.05
       Average shared text size (kbytes): 0
       Average unshared data size (kbytes): 0
       Average stack size (kbytes): 0
       Average total size (kbytes): 0
       Maximum resident set size (kbytes): 0
       Average resident set size (kbytes): 0
       Major (requiring I/O) page faults: 0
       Minor (reclaiming a frame) page faults: 210
       Voluntary context switches: 2
       Involuntary context switches: 1
       Swaps: 0
       File system inputs: 0
       File system outputs: 0
       Socket messages sent: 0
       Socket messages received: 0
       Signals delivered: 0
       Page size (bytes): 4096
       Exit status: 0

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