pi icecast to fm with rds metadata via pifmrds

#!/bin/bash
FRQ=88.5
SID=0420
PPM=22
SSID="TEST"
F_RDS="TEST"
F_FILE="http://10.42.0.13:5738/stream"
F_META="http://10.42.0.13:5738/rds.xsl"
F_CTL="/root/_fmctl"


Z_RAD_PID=0

trap ctrl_c INT

function ctrl_c() {
        echo "** Caught CTRL-C"
        if [ ${Z_RAD_PID} > 0 ] ; then
                echo "** Stopping transmission"
                kill ${Z_RAD_PID} 2>/dev/null
                if [ -e "${F_CTL}" ]; then
                        echo "** Cleaning up transmitter control pipe"
                        rm -f "${F_CTL}"
                fi

                exit
        fi
}

if [ ! -e "${F_CTL}" ]; then
        mkfifo "${F_CTL}"
fi

cd /home/pi/dev/rpitx
ffmpeg -loglevel warning -i "${F_FILE}" -c:a pcm_s16le -ac 2 -ar 48000 -f wav - | \
./pifmrds -freq ${FRQ} -ppm ${PPM} -pi ${SID} -ps ${SSID} -rt "${F_RDS}" -ctl "${F_CTL}" -audio - &
Z_RAD_PID=$!


METADATA=""
METADATA_L=""
while (true); do
        METADATA=$(curl -sL "${F_META}")
        if [ "${METADATA}" != "${METADATA_L}" ]; then
                if [ -e "${F_CTL}" ]; then
                        # ctl stuff
#                       echo "PS ${SSID}" > "${F_CTL}"
                        echo "RT ${METADATA}" > "${F_CTL}"
                fi
                METADATA_L="${METADATA}"
        fi
        sleep 3;
done