CODEWITHSUNDEEP
unixdatetimeunix-timestamp
VRVigneshwara
VRVigneshwara

Reputation: 1087

Difference in two dates in unix shell scripting

I have a two dates in date +"%Y%m%d%H%M%S" format. How to find the difference and how to check whether the difference is more than 4 hours? This is how i have tried

echo $(( ( $(date +"%Y%m%d%H%M%S") - $(date +"%Y%m%d%H%M%S" -d "1970-01-01 + $(stat -c '%Z' filename ) secs"))))

date command returns this

Sun Sep  6 10:35:19 CDT 2015

Upvotes: 1

Views: 1123

Answers (1)

ehaymore
ehaymore

Reputation: 217

This shell function uses the GNU date utility to convert your date string to seconds since the epoch:

function dateconv() {
    date --date=${1:0:4}-${1:4:2}-${1:6:2}T${1:8:2}:${1:10:2}:${1:12:2} +%s
}

It inserts hyphens, colons, and a T to convert it to the ISO 8601 format that date understands as an input format.

With that defined, you can do something like this to check the difference between two strings in variables d1 and d2:

if [ $(( $(dateconv $d2) - $(dateconv $d1) )) -gt 14400 ]
then
    echo Difference is more than 4 hours
fi

It converts both date strings to seconds, subtracts them, and checks if the difference is more than 14400 seconds (4 hours).

Upvotes: 1

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