#! /bin/bash
function send_data
{
	trap send_data SIGPIPE 
	while read line
	do
		case $line in
		\$GPVTG*)
			echo "$line"
			sleep 1	
			;;
		*)	
			echo "$line"
			;;
		esac
	done <track/all.txt >/tmp/gpsdata
}

send_data