Converting seconds to minutes

Shell Programming and Scripting
1

Hello everyone,

I calculate in my bash script the different between two timestamps in seconds. The next step would be to get the difference in minutes, and there is my Problem:

AnzahlUeberstunden=$(( $(date -d "$JAHR-$MONAT-$TAG $ArbeitEnde" +%s) - $(date -d "$JAHR-$MONAT-$TAG $NormalesArbeitsEnde" +%s) ))

This is the code I calculate the seconds. Normally I would say that I only need to do: AnzahlUeberstunden=$Anzahueberstunden/60 but when I print this I get: 2040/60 What am I doing wrong? The count of seconds is right with 2040......

Thanks for all hints

Steve

2

Try the same as de line above with $(( ... )) en some corrections in the variable name..

AnzahlUeberstunden=$((AnzahlUeberstunden/60))

or

(( AnzahlUeberstunden/=60 ))
3

Why do i have to put tags around it?

4

Because it is a an arithmetic operation (you are trying to divide a number by 60)

Therefore you need an arithmetic expansion ( see: Shell command language: arithmetic expansions )
so you can assign the result of the arithmetic expression to a variable (assignment means variable=value )

If you do not do that, in your example AnzahlUeberstunden=$AnzahlUeberstunden/60 what happens is that you assign the value of AnzahlUeberstunden concatenated with the text string /60 , so the result becomes 2040/60 .

--
My second suggestion is called an arithmetic expression (which can be used in shells like ksh93, bash, zsh) in which variables can be modified without an explicit variable assignment.

1 Like
5

Hi
look at this way

declare -i AnzahlUeberstunden
AnzahlUeberstunden=$(date -d "$JAHR-$MONAT-$TAG $ArbeitEnde" +%s)-$(date -d "$JAHR-$MONAT-$TAG $NormalesArbeitsEnde" +%s) #"tags" are not needed
AnzahlUeberstunden=AnzahlUeberstunden/60 #dollar sign is not needed
echo $AnzahlUeberstunden
34

Please note there should not be spaces around the minus sign

2 Likes
6

Hi Chaos_Lord...

Just an observation; you have shown figures that apparently create a true integer value on integer division...
What happens if the number of seconds is not fully divisible by 60?
Do you just want the integer division, round down and/or round up, or a floating point value?

7

One could also use quotes:

AnzahlUeberstunden="$(date -d "$JAHR-$MONAT-$TAG $ArbeitEnde" +%s) - $(date -d "$JAHR-$MONAT-$TAG $NormalesArbeitsEnde" +%s)"

AnzahlUeberstunden='AnzahlUeberstunden / 60'
2 Likes