SOLVED: BASH script to parse data from /dev/xxx and output to command

I'm trying to find a way to have a bash script read data that another piece of software is sending to a /dev port (such as tty/pts/usb/serial). Specifically I'm looking to grab output from "hamlib" (which apparently only sends to certain /dev ports, NOT a txt file!) and parse the output for use with servoblaster. My script works like a charm when the input is a text file, but I've been unable to find a way to link it back to hamlib. A piped FIFO buffer would probably be great if I could make it work...

Here's the script:

Code:

#!/bin/bash

fil=/usr/src/testdata
#fil=/dev/tty20

function hamlibmon()
{

while read line
do
echo $line | grep -q EL
if [ $? == 0 ]; then
elpos=`echo $line | cut -d L -f2 | cut -d . -f1`
elpos=$(echo "scale=3; $elpos*1.1+50" | bc)
echo 0=$elpos > /dev/servoblaster
fi
done < $fil

}

while true
do
hamlibmon
done

fi

 

Ended up using /dev/vcs20 to read data sent to /dev/tty20:

Code:

#!/bin/bash

#Written 2015-02-28 by VE6WK with assistance from AI6GS
#This script assumes hamlib started with: rotctld -m 202 -r /dev/tty20

azservnum=0      #Azimuth servo number for Servoblaster
azservstart=50   #Starting position for azimuth servo, usually 50
azservend=250    #Ending position for azimuth servo, usually 250
elservnum=1      #Elevation servo number for Servoblaster
elservstart=50   #Starting position for elevation servo, usually 50
elservend=250    #Ending position for elevation servo, usually 250

azfactor=$(echo "scale=1; ($azservend-$azservstart)/360" | bc)
elfactor=$(echo "scale=1; ($elservend-$elservstart)/180" | bc)

fil=/tmp/rotcmd.txt

function hamlibmon()
{

tail -c 350 /dev/vcs20 > /tmp/rotcmd.txt
sed -i -e '$a\' /tmp/rotcmd.txt

  while read line
  do
    echo $line | grep -q EL
    if [ $? == 0 ]; then
    azpos=`echo $line  | cut -d Z -f2 | cut -d . -f1`
    azpos=$(echo "scale=1; $azpos*$azfactor+$azservstart" | bc)
    elpos=`echo $line  | cut -d L -f2 | cut -d . -f1`
    elpos=$(echo "scale=1; $elpos*$elfactor+$elservstart" | bc)
    echo $azservnum=$azpos > /dev/servoblaster
    echo $elservnum=$elpos > /dev/servoblaster
    fi
  done < $fil

}

while true
do
        hamlibmon
        sleep .5
done

fi