chrono.sh

#!/bin/sh

#set -x
#elapsed=12345600

while true; do
	s=$(( ${elapsed:-0} / 100 ))
	d_=$(( $s / 86400 ))
	s=$(( $s % 86400 ))
	h_=$(( $s / 3600 ))
	s=$(( $s % 3600 ))
	m_=$(( $s / 60 ))
	s=$(( $s % 60 ))
	s_=$(( $s ))
	ms_=$(( ${elapsed:-0} - ( ${elapsed:-0} / 100 ) * 100 ))

	printf -- '\r%2d h %2d m %2d s %02d ms (total: %5d ms) %s' \
		"$h_" "$m_" "$s_" "$ms_" "$elapsed" "press: [enter] to pause [ctrl+c] to stop"
	sleep 0.01
	elapsed=$(( $elapsed + 1 ))
done