#!/bin/sh

get_mtime() {
	echo $(stat -c %Y /proc/$1 2>/dev/null)
}

if [ $# -ne 1 ] ; then
	echo "Usage: $0 <pid>" >&2
	exit 1
fi

mtime=$(get_mtime $1)
if [ -z "$mtime" ] ; then
	echo "Pid $1 not found" >&2
	exit 1
fi

while [ "$(get_mtime $1)" = "$mtime" ] ; do
	sleep 1
done