Difference between two dates

UNIX for Beginners Q & A
1

Hi There

I am trying to find the difference between two dates in seconds, by taking the first 10 digits of the file name itself, which I have done as shown below:

current_time=`date +%s`
last_login_of_tim=`date -d @1489662376 +%s`
 diff_sec=$(($current_time-$last_login_of_tim))

This will return the date in seconds.

However what I am stuck with is that the file I want to return the date from, in the name it has the date and time of last execution, I tried to do the same way but this failed.

File Name: 'Wynyard_MTP_Primary-btstats-2017-03-29-10:34:50.xml'

How can I now do what I done before but with this file?

Any help would be greatly appreciated

Thanks in advanced

2

Please elaborate how you did "do the same way", and also post the way "this failed".
Where and how is that file name stored? A shell variable? In a loop?

Are you aware that date -d @1489662376 +%s is a NoOP?

3

Hi RudiC

Sorry yes i will.

So first of all i'm not sure what you mean by a NoOP?

& by meaning same process I mean taking the first 10 digits but as there are "-" between day month year etc it won't except, is there another way to execute this?

4

NoOp (No Operation) means "do nothing". Look at the result:

date -d @1489662376 +%s
1489662376

Why didn't you answer ALL questions?

5

Hi @RudiC

Sorry for the late reply

So yes I have just noticed that this is a no operation, so I want to find the difference between the dates with two files and have a round number (if possible in minutes/seconds)

So for example to days date = date = Tue Apr 4 11:05:18 BST 2017
The date of the particular file = date -d @1489662376 = Thu Mar 16 11:06:16 GMT 2017

Is there away to calculate the difference in minutes or seconds in this case would be roughly 27,359 minutes or 1,641,542 seconds. Is there a way to get this answer?

Thanks
simpsa27

6

Hi.

See package dateutils, which can be found in many repositories, and includes ddiff :

NAME
       ddiff  -  Compute  duration from DATE/TIME (the reference date/time) to
       the other

SYNOPSIS
       ddiff [OPTION]... DATE/TIME [DATE/TIME]...

DESCRIPTION
       Compute duration from DATE/TIME (the reference date/time) to the  other
       DATE/TIMEs  given  and  print  the  result  as  duration.  If the other
       DATE/TIMEs are omitted read them from stdin.
...
       Time specs:
         %H  Durations in hours
         %I  Equivalent to %H
         %M  Durations in minutes
         %S  Durations in seconds
...

Some additional details:

dateutils.ddiff Compute duration from DATE/TIME (the reference date/ti... (man)
Path    : /usr/bin/dateutils.ddiff
Version : 0.3.1
Type    : ELF 64-bit LSB shared object, x86-64, version 1 (S ...)
Help    : probably available with -h,--help
Home    : https://github.com/hroptatyr/dateutils

The package utilities take some practice to learn, but are very useful for dealing with almost any form of date and time data.

Best wishes ... cheers, drl