add quotes around PYTHON; add check for esptool

bin/device-install.sh

@@ -11,7 +11,7 @@ Usage: $(basename $0) [-h] [-p ESPTOOL_PORT] [-P PYTHON] [-f FILENAME|FILENAME]
 Flash image file to device, but first erasing and writing system information"
 
     -h               Display this help and exit
-    -p ESPTOOL_PORT  Set the environment variable for ESPTOOL_PORT.  If not set, ESPTOOL iterates all ports (Dangerrous).
+    -p ESPTOOL_PORT  Set the environment variable for ESPTOOL_PORT.  If not set, ESPTOOL iterates all ports (Dangerous).
     -P PYTHON        Specify alternate python interpreter to use to invoke esptool. (Default: "$PYTHON")
     -f FILENAME      The .bin file to flash.  Custom to your device type and region.
 EOF
@@ -44,12 +44,15 @@ shift "$((OPTIND-1))"
     shift
 }
 
+# check that esptool is installed
+"$PYTHON" -m esptool -h >/dev/null 2>&1 || echo "Error: esptool was not found."; exit 1
+
 if [ -f "${FILENAME}" ]; then
 	echo "Trying to flash ${FILENAME}, but first erasing and writing system information"
-	$PYTHON -m esptool  erase_flash
-	$PYTHON -m esptool  write_flash 0x1000 system-info.bin
-	$PYTHON -m esptool  write_flash 0x00390000 spiffs-*.bin
-	$PYTHON -m esptool  write_flash 0x10000 ${FILENAME}
+	"$PYTHON" -m esptool  erase_flash
+	"$PYTHON" -m esptool  write_flash 0x1000 system-info.bin
+	"$PYTHON" -m esptool  write_flash 0x00390000 spiffs-*.bin
+	"$PYTHON" -m esptool  write_flash 0x10000 ${FILENAME}
 else
 	echo "Invalid file: ${FILENAME}"
 	show_help