Spinning Wheel Animation

#!/bin/bash

# Simple spinning wheel to show something
# is loading, or to show data is being updated
# and not stale.
# Arguments:
#	1 = index [required]; if not provided, will reset to zero.
function wheel() {
	chars="|/-\\"
	index=$1
	if [[ index -lt 0 ]]
	then
		index=0
	elif [[ index -ge 3 ]]
	then
		index=0
	else
		index=$((index + 1))
	fi
	echo ${chars:$index:1}
}