Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

Calculating Elapsed Time in Bash Shell on Oracle Linux 6.5

Posted on 2014-04-12
3
650 Views
Last Modified: 2014-04-17
I want to be able to take calulate milliseconds by taking an input and then returning elapsed time as HH:MM:SS.NNN

I was taking this code (http://www.linuxjournal.com/content/use-date-command-measure-elapsed-time) as my basis and trying to expand to include milliseconds...but I am getting into a right old mess with the math

The original code works fine:
#!/bin/bash

function timer()
{
    if [[ $# -eq 0 ]]; then
        echo $(date '+%s')
    else
        local  stime=$1
        etime=$(date '+%s')

        if [[ -z "$stime" ]]; then stime=$etime; fi

        dt=$((etime - stime))
        ds=$((dt % 60))
        dm=$(((dt / 60) % 60))
        dh=$((dt / 3600))
        printf '%d:%02d:%02d' $dh $dm $ds
    fi
}

#test the function
start=$(timer)
sleep 5
stop=$(timer $start)
echo "Elapsed time: $stop " 

Elapsed time: 0:00:05

Open in new window


Now I want to take the input to be milliseconds (rather than seconds) and return HH:MM:SS.NNN.  I did this but it fails horribly:

#!/bin/bash

function timer2()
{
    if [[ $# -eq 0 ]]; then
        echo $(date '+%s%N')

    else
        local  stime=$1
        etime=$(date '+%s%N')

        if [[ -z "$stime" ]]; then stime=$etime; fi

        dt=$((etime - stime))
        dn=  ## QUESTION:  how do I set the milliseconds to 3 places (not 9)
        ds=$(((dt % (1000*60*60)) % (1000*60)) / 1000)
        dm=$(((dt % (1000*60*60)) / (1000*60)  ))
        dh=$(( dt / (1000*60*60)))
        printf '%d:%02d:%02d.%03d' $dh $dm $ds $dn
    fi
}

# test function
start=$(timer2)
sleep 2
stop=$(timer2 $start)
echo "Elapsed time: $stop " 

Open in new window


How do I set dn for the milliseconds and what is the correct math to get desired out put?

Any help would be greatly appreciated.
0
Comment
Question by:klyles95
  • 2
3 Comments
 
LVL 68

Accepted Solution

by:
woolmilkporc earned 500 total points
ID: 39996833
%N means nanoseconds (1 sec = 1000000000 nanoseconds).
So you'll have to use 1000000000 or (1000*1000*1000) instead of just 1000.

To get milliseconds you must perform an integer division by (1000*1000) after calculating the remainder of the division by (1000*1000*1000)

This should work: (the script expects the "sleep" seconds as a command line parameter):

#!/bin/bash
function timer2()
{
    if [[ $# -eq 0 ]]; then
        echo $(date '+%s%N')

    else
        local  stime=$1
        etime=$(date '+%s%N')

        if [[ -z "$stime" ]]; then stime=$etime; fi

        dt=$((etime - stime))
        dn=$((dt % (1000*1000*1000)/(1000*1000)))
        ds=$((dt / (1000*1000*1000)%(60*60)%60))
        dm=$((dt / (1000*1000*1000)%(60*60)/60))
        dh=$((dt / (1000*1000*1000)/(60*60)))
        printf '%d:%02d:%02d.%03d' $dh $dm $ds $dn
    fi
}

# test function
start=$(timer2)
sleep $1
stop=$(timer2 $start)
echo "Elapsed time: $stop "

Open in new window

I have to leave now, sorry! If I made a mistake (I probably did) let's talk about it tomorrow!

EDIT: If you want to half-adjust the miliseconds then calculate "dn" like this:

dn=$(((dt+500000) % (1000*1000*1000)/(1000*1000)))

wmp
0
 

Author Comment

by:klyles95
ID: 40007975
Thank you wmp - this didnt quite  work.  I was getting the same result returned.  

I ended up doing this calculation differently by separating the milliseconds from the seconds and doing the math that way.

Thank you for responding
0
 
LVL 68

Expert Comment

by:woolmilkporc
ID: 40007996
You could have asked me to improve my work instead of giving a grade C straightaway.
0

Featured Post

Comprehensive Backup Solutions for Microsoft

Acronis protects the complete Microsoft technology stack: Windows Server, Windows PC, laptop and Surface data; Microsoft business applications; Microsoft Hyper-V; Azure VMs; Microsoft Windows Server 2016; Microsoft Exchange 2016 and SQL Server 2016.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Over the last ten+ years I have seen Linux configuration tools come and go. In the early days there was the tried-and-true, all-powerful linuxconf that many thought would remain the one and only Linux configuration tool until the end of times. Well,…
Setting up Secure Ubuntu server on VMware 1.      Insert the Ubuntu Server distribution CD or attach the ISO of the CD which is in the “Datastore”. Note that it is important to install the x64 edition on servers, not the X86 editions. 2.      Power on th…
Learn several ways to interact with files and get file information from the bash shell. ls lists the contents of a directory: Using the -a flag displays hidden files: Using the -l flag formats the output in a long list: The file command gives us mor…
This demo shows you how to set up the containerized NetScaler CPX with NetScaler Management and Analytics System in a non-routable Mesos/Marathon environment for use with Micro-Services applications.

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question