usb-enum

#!/bin/bash
# /etc/default/usb-enum
# Helper script to find marine USB devices
#

mtty=$(ls /dev/ttyUSB-GPS /dev/ttyUSB-AIS /dev/ttyUSB-RAY 2>/dev/null | wc -w)
if [ $mtty -gt 2 ]; then exit 0; fi

nd=$(ls /dev/ttyUSB[[:digit:]] 2>/dev/null | wc -w)
if [ $nd -eq 0 ]; then exit 0; fi

let nd=$nd-1

for ((d=0; d<=$nd; d++))
do
    lsof /dev/ttyUSB${d} > /dev/null 2>&1
    if [ $? -eq 0 ]; then
        devs[${d}]=1
    else
        devs[${d}]=0
    fi
done

for ((d=0; d<=$nd; d++))
do
    if [ ${devs[${d}]} -eq 1 ]; then continue; fi

    stty -F /dev/ttyUSB${d} speed 38400  > /dev/null 2>&1 
    timeout 4 egrep -q -m 1 'AIVDM|AIVDO' /dev/ttyUSB${d}
    if [ $? -eq 0 ]; then
        rm -f /dev/ttyUSB-AIS
        ln -s /dev/ttyUSB${d} /dev/ttyUSB-AIS
        devs[${d}]=1
        break
    fi
done

for ((d=0; d<=$nd; d++))
do
    if [ ${devs[${d}]} -eq 1 ]; then continue; fi

    stty -F /dev/ttyUSB${d} speed 38400  > /dev/null 2>&1 
    timeout 4 grep -q -m 1 "GPRMC" /dev/ttyUSB${d}
    if [ $? -eq 0 ]; then
        rm -f /dev/ttyUSB-GPS
        ln -s /dev/ttyUSB${d} /dev/ttyUSB-GPS
        devs[${d}]=1
        break
    fi
done

for ((d=0; d<=$nd; d++))
do
    # Default
    if [ ${devs[${d}]} -eq 0 ]; then
        if [ -c  /dev/ttyUSB${d} ]; then
            rm -f /dev/ttyUSB-RAY
            ln -s /dev/ttyUSB${d} /dev/ttyUSB-RAY
            break;
        fi
    fi
done

exit 0