btconnect

#!/bin/bash

# script to ease connecting to an NXT brick
# (c) 2007-2009 Johannes Ballé

# test if syntax is correct; if not, print help and exit

if [ $# = 0 -o $# -gt 2 ] || [ "$1" = "--help" -o "$1" = "-h" ] || ! { [ $# = 1 ] || [ "$2" -ge 0 ] 2>/dev/null; }; then
	cat <<-END_HELP >&2
		${0##*/} <MAC address/device name> [rfcomm device number]

		${0##*/} establishes a persistent connection to the MAC address
		or device name given in the first argument. The second, optional argument
		specifies which rfcomm device should be used. If omitted, the first
		available device will be used.

		Once the connection is established, ${0##*/} waits until it receives
		any termination signal (which happens, for instance, when Ctrl-C is
		pressed or the shell window is closed). Then, the connection is
		taken down.

		Examples:

		${0##*/} NXT-20-B 2

		This connects the NXT brick named "NXT-20-B" to rfcomm2.

		${0##*/} 00:16:53:06:D8:67

		This connects the NXT brick with the hardware address 00:16:53:06:D8:67
		to the first available rfcomm device (if no others are used, this will
		be rfcomm0).

		Depending on your Linux distribution, you will find the rfcomm device file
		either at /dev/rfcommX or /dev/bluetooth/rfcommX.
	END_HELP
	exit 128
fi

# if device name is given, check if it's already used

if [ $# = 2 ]; then
	(( DEVICE=$2 ))
	if [ -e /dev/rfcomm$DEVICE -o -e /dev/bluetooth/rfcomm$DEVICE ]; then
		echo "rfcomm$DEVICE is already in use!"
		exit 3
	fi
fi

# if hardware address is given, we're all set. otherwise, perform a scan

if [[ $1 =~ "^[0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}$" ]]; then
	MAC=$1
else
	NAME="$1"
	echo -n "Scanning for '$NAME' ... " >&2
	MAC=$( hcitool scan | awk -F '\t' '$2 ~ /^([0-9a-fA-F]+:)+[0-9a-fA-F]+$/ && $3 == "'"$NAME"'" { print $2 }' )
	if [ -z $MAC ]; then
		echo "not found." >&2
		exit 1
	fi
	if [[ "$MAC" == "*\ *" ]]; then
		echo "found multiple devices:" >&2
		echo >&2
		for i in $MAC; do
			echo '	'$i >&2
		done
		echo >&2
		echo "Use ${0##*/} with one of the addresses above." >&2
		exit 2
	fi
	echo "found $MAC." >&2
fi

# if device is not given, find first unused device

if [ -z $DEVICE ]; then
	(( DEVICE=0 ))
	while [ -e /dev/rfcomm$DEVICE -o -e /dev/bluetooth/rfcomm$DEVICE ]; do
		(( DEVICE++ ))
	done
fi

rfcomm -r connect rfcomm$DEVICE $MAC &

trap "kill $!" 1 3 9 15
wait