sleepy

#!/bin/sh
## Interactive sleep:
#
# + increase by 10 seconds
# - decrease by 10 seconds
# q stop sleeping
# anything else prints remaining time

t=${1:-1}
ts="$t"

case "$t" in
	*s) tm=${t%*s} t=$(($tm)) ;;
	*m) tm=${t%*m} t=$(($tm * 60)) ;;
	*h) tm=${t%*h} t=$(($tm * 60 * 60)) ;;
	*d) tm=${t%*d} t=$(($tm * 60 * 60 * 24)) ;;
	*[0-9]) : ;;
	*) echo "ERROR: unknown timestamp"; exit 1;;
esac

while :; do
	[ "$t" -le 0 ] && break
	read -n 1 -t 1 ch
	ret=$?
	if [ $ret = 142 ]; then
		# timeout
		:
	elif [ $ret = 0 ]; then
		# keypress
		echo "sleep for $ts, remaining" `TZ=utc date --date=@$t +%H:%M:%S` "($t)"
		if [ "$ch" = 'q' ]; then
			echo "quit"
			exit 0
		elif [ "$ch" = '+' ]; then
			echo "increase by 10s"
			t=$(($t + 10 - 1))
		elif [ "$ch" = '-' ]; then
			echo "decrease by 10s"
			t=$(($t - 10 - 1))
		fi
		t=$(($t + 1))
	fi
	t=$(($t - 1))
done