Compare two timestamps and print elapsed time

Shell Programming and Scripting
1

Hi,
I am unable to Difference between two time stamps in Linux and display the total elapsed time .

Source date: Aug 15, 2012 02:00:03
Target date: Aug 14, 2012 18:00:03

# based on the forums I am using the below function. Converted dates into this format

Src_dt=20120814180003
Tgt_dt=20120815020003
Total=`expr $Tgt_dt - $Src_dt`
Echo $Total

I am unable to get the proper output. I should get like this (total elapsed time: 08:00:00).

Does Linux having any direct command to difference between two timestamps and giving the total elapsed time,

Any suggestions, greatly appreciated.

Thanks
onesuri

2

One way would be to use the special date formatting capabilities of the printf builtin of the kornshell 93:

#!/bin/ksh93

src=$( printf "%(%s)T\n" 201208141800.03 )
tgt=$( printf "%(%s)T\n" 201208150200.03 )

TZ= printf "%(%T)T\n" '#'$(( tgt - src ))

Output:

08:00:00
3

Assumed you are talking of file time stamps, the stat --printf "%X" filename will output seconds since epoch, which can easily subtracted/converted. Use %Y or %Z for file's other timestamps.

4

Hi,

Thanks for the suggestion,
I have tried the same way but I am getting the below error. I am using the LINUX environment. Do i need to use different format for the below commands.

Sample.sh: line 5: printf: `(�: invalid format character
Sample.sh: line 6: printf: `(�: invalid format character
Sample.sh: line 7: printf: `(�: invalid format character

Thanks -onesuri

5

You seem to use the standard printf command. My solution only works with the kornshell 93 and it's builtin printf command.

6

Please provide the output for the src,tgt and TZ. it will easy to find the relevent command

src=$( printf "%(%s)T\n" 201208141800.03 )
tgt=$( printf "%(%s)T\n" 201208150200.03 )

TZ= printf "%(%T)T\n" '#'$(( tgt - src ))
7

src, tgt and TZ are shell variables, not commands. Look for a command "ksh93" on your system (usually /bin/ksh93). If this command is not present, you have to install the kornshell 93 or find a different approach.

---------- Post updated at 11:04 ---------- Previous update was at 11:00 ----------

Ahh, I think I misunderstood you.

src and tgt will hold the timestamps converted to the internal unix time representation

src = 1344960003
tgt = 1344988803

TZ is the timezone variable and has to be cleared, so that the correct time difference is printed, because it is actually not a time difference, but a timestamp relative to the first of january, 1970.

8

Hi,

Try this

Src_dt="Aug 15, 2012 02:00:03"
Tgt_dt="Aug 14, 2012 18:00:03"
Total=$(expr $(date -d "$Src_dt"  +%s) - $(date -d "$Tgt_dt" +%s))
echo $Total | awk '{printf "Elapsed time: %02d:%02d:%02d\n",$1/(60*60),$1%(60*60)/60,$1%60}'

Output will be.

Elapsed time: 08:00:00