Add usbgetty to source tree

setup/usbgetty.txt

@@ -0,0 +1,47 @@
+#!/bin/bash
+
+ttyUSB=
+
+pkill -f "sleep 86399"
+
+if [[ $(grep -e '-scanttyUSB' <<< "$*") ]]; then
+    # called with -scantty isntead of device name?
+    # echo "-scantty mode"
+
+    # if upper USB port
+    if [[ -c /dev/ttyUSBupper ]]; then
+        ttyUSB=ttyUSBupper
+
+    # if hub in upper port, use highest numbered port on hub
+    elif [[ $(ls -1 /dev/ttyUSBupper_hub* 2> /dev/null | wc -l) -gt 0 ]]; then
+        ttyUSB=$(ls -1 /dev/ttyUSBupper_hub* 2> /dev/null | tail -1 | cut -c 6-)
+
+    # if hub in lower port with multiple adapters, use highest numbered port on hub
+    elif [[ $(ls -1 /dev/ttyUSBlower_hub* 2> /dev/null | wc -l) -gt 1 ]]; then
+        ttyUSB=$(ls -1 /dev/ttyUSBlower_hub* 2> /dev/null | tail -1 | cut -c 6-)
+
+    # no port found eligible for getty
+    else
+        # echo "scantty no devices eligible: sleeping"
+        sleep 86399
+    fi
+    
+    # echo "result:$ttyUSB"
+elif [[ $(grep -o 'ttyUSB[^ ]*' <<< "$*") ]]; then
+    # echo "device specified"
+    # if specified USB device name is found
+    ttyUSB=$(grep -o 'ttyUSB[^ ]*' <<< "$*")
+else
+    # echo "specified device failed: sleeping"
+    sleep 86399
+fi
+
+if [[ -c /dev/$ttyUSB && ! $(ps aux | grep "[g]etty.*$ttyUSB") ]]; then
+    # if adapter seems to exist and doesn't already have a getty,
+    #   kill all USB gettys and start the getty, otherwise do nothing
+    pkill -f "/sbin/getty.*ttyUSB"
+    exec /sbin/getty $(sed "s/-scanttyUSB/$ttyUSB/" <<< "$@");
+else
+    # echo "getty already running or doesn't exist: sleeping"
+    sleep 86399
+fi