function stopwatch() for bash/zsh

stopwatch.sh

# simple stopwatch function
# scripted by github.com/thonixx
function stopwatch () {
	########
	# config
	
	# initialise seconds and start with second 1
	sec=1
	# define maximum of dots to display
	maxdots=10
	# initialise count for the dots at the beginning
	startdot=1
	# date when stopwatch was started
	startdate=$(date +%s)
	
	# start the first output with current time
	echo "Stopwatch started: $(date -d @$startdate)"

	# while loop to count the seconds
	while [ true ] 
	do
		# calculate the time based on date
		let "sec = $(date +%s) - $startdate + 1"

		# display seconds if under 1 minute
		if [ "$sec" -lt 60 ]
			# fill time with raw seconds
			then time="$sec"
		# switch to minutes if more than 60 seconds
		else min=$(expr $sec / 60)
			# calculate the seconds minus the minutes
			relSec=$(expr $sec - $min \* 60)
			# fill time with minutes and relative seconds
			time="$min"'m'" $relSec"
		fi
		
		# define the dots (just for beauty)
		dotloop=0
		
		# reset the variable
		dotPrint=""
		
		# print the dots
		while [ "$dotloop" -lt "$startdot" ]
		do
			# append
			dotPrint="$dotPrint."
			# increase
			let "dotloop = dotloop + 1"
		done
		
		# calculate required spaces
		actualChars=$(echo -n "$dotPrint" | wc -c)
		spacesToPrint=$(expr $maxdots - $actualChars)
		
		# add the spaces
		spacesAdded=0
		
		# initialise output
		spaces=""
		
		# add the required spaces
		while [ "$spacesAdded" -lt "$spacesToPrint" ]
		do
			# append the white spaces
			spaces="$spaces "
			
			# calculate spaces left
			let "spacesAdded = $spacesAdded + 1"
		done
		
		# merge dots and spaces
		dotPrint="$dotPrint$spaces"
		
		# print the current time
		# http://stackoverflow.com/questions/11283625/bash-overwrite-last-terminal-line
		echo -ne "\e[0K\r   Time: $time"'s'" $dotPrint "
		
		# wait a second before continueing
		sleep 1 || echo "hi"
		
		# calculate the next count for the dots
		startdot=$(if [ "$startdot" -lt "$maxdots" ]; then expr $startdot + 1; else echo "1"; fi)
	done
}