CODEWITHSUNDEEP
bashshellksh
v3rd1ct
v3rd1ct

Reputation: 67

Shell script to compare the time difference and alert if greater than 5 minutes?

I am trying to create a script in AIX (ksh/bash) where I need to compare two variables with two different date formats, and raise an alert if the difference between the StartTime and CurrentTime is greater than 5 minutes.

As an example, if I have a script that has these three variables:

StartTime="20 Oct 2022 12:20:48 -0700"
CurrentTime=$(date)
AlertThreshold=300

How can I compare the two, and do something if the difference between StartTime and CurrentTime is greater than AlertThreshold (300 seconds)?

The value returned by $(date) is in this format: Thu Oct 20 12:37:05 PDT 2022

I am stuck trying to figure out a way to convert both variables to a format where I can compare the values, so that I can test to see if the time difference is greater than AlertThreshold.

I assume both would need to be converted to unix timestamp to compare?

Any help would be appreciated.

date command usage:

[mmddHHMM[[cc]yy]] [+"Field Descriptors"]
Usage: date [-n][-u] [mmddHHMM[.SS[cc]yy]] [+"Field Descriptors"]
Usage: date [-a [+|-]sss[.fff]]

Upvotes: 0

Views: 1104

Answers (2)

Fravadona
Fravadona

Reputation: 17216

You could use perl:

if perl -MDate::Parse -e '
   exit( str2time($ARGV[1]) - str2time($ARGV[0]) <= $ARGV[2] )
   ' "$StartTime" "$CurrentTime" "$AlertThreshold"
then
    echo alert
fi

Or a 100% portable way that you can adapt to your time formats; it shouldn't be too difficult as long as the timezones are the same for the two dates.

Upvotes: 1

Adam Liss
Adam Liss

Reputation: 48330

This should do what you want. The key is to use date to convert the dates to seconds, and then the rest is straightforward. If you don't need the times to be human-readable, you can use, e.g., currentTime="$(date +%s)" and work exclusively in seconds.

#!/bin/bash
startTime="20 Oct 2022 12:20:48 -0700"
currentTime="$(date)"
alertThreshold=300

# Convert dates to seconds.
currSec=$(date -d "${currentTime}" +%s)
startSec=$(date -d "${startTime}" +%s)

if ((currSec - startSec > alertThreshold)); then
  echo "Alert!"
else
  echo "Keep waiting."
fi

Upvotes: 1

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