Bash - Example of measuring elapsed time

MeasureElapsedTime.sh

#!/bin/bash

#############################################
# Determines how much time has elapsed.
#
# Takes advantage of the 'SECONDS' variable which is global environment variable in shell.
# 'SECONDS' is usually used by the environment to record how long it has been
#     since a script was first executed.
#
# It's taken advantage of here to measure a length of time.
#############################################

# You can reset the 'SECONDS' variable whenever you want.
# This can be handy if you are using it as a timer, as resetting it will then reset your timer.
SECONDS=0


## Uncomment any of the lines below to get the elapsed time in different increments.
# Elapsed time in minutes
#ELAPSEDTIME=$((SECONDS / 60))

# Elapsed time in hours
#ELAPSEDTIME=$((SECONDS / 3600))

# Elapsed time in days
#ELAPSEDTIME=$((SECONDS / 86400))

echo "$ELAPSEDTIME"