diff --git a/libraries/AP_Scripting/applets/Hexsoon LEDs.lua b/libraries/AP_Scripting/applets/Hexsoon LEDs.lua
index 142e1e49b7..29b0cad6e9 100644
--- a/libraries/AP_Scripting/applets/Hexsoon LEDs.lua	
+++ b/libraries/AP_Scripting/applets/Hexsoon LEDs.lua	
@@ -25,12 +25,11 @@ LEDs should now work!, if not try swapping AUX 5 and 6, either by physically swa
 To get colours to match either change the ordering in "local led_map ="  below or swap headers round on the LED distribution board
 If using 6 les add two extra colours to "local led_map =" e.g:  "local led_map = {red, red, red, green, green, green}"
 --]]
--- luacheck: only 0
 
 -- helper colours, red, green, blue values from 0 to 255
 local red   = {255, 0,   0}
 local green = {0,   255, 0}
-local blue =  {0,   0,   255}
+-- local blue =  {0,   0,   255}
 
 -- led map giving the colour for the LEDs plugged in
 local led_map = {red, red, green, green}
diff --git a/libraries/AP_Scripting/examples/Serial_Dump.lua b/libraries/AP_Scripting/examples/Serial_Dump.lua
index 926a97353e..bfff5392e8 100644
--- a/libraries/AP_Scripting/examples/Serial_Dump.lua
+++ b/libraries/AP_Scripting/examples/Serial_Dump.lua
@@ -1,5 +1,4 @@
 -- this script reads data from a serial port and dumps it to a file
--- luacheck: only 0
 
 local file_name = 'raw serial dump.txt'
 local file_name_plain = 'serial dump.txt'
@@ -11,6 +10,7 @@ local port = assert(serial:find_serial(0),"Could not find Scripting Serial Port"
 
 -- make a file
 local file = assert(io.open(file_name, "w"),"Could not create file " .. file_name)
+file:close()
 file = assert(io.open(file_name_plain, "w"),"Could not create file " .. file_name)
 file:close()
 
diff --git a/libraries/AP_Scripting/examples/aux_cached.lua b/libraries/AP_Scripting/examples/aux_cached.lua
index 1e514055a9..e029c44e98 100644
--- a/libraries/AP_Scripting/examples/aux_cached.lua
+++ b/libraries/AP_Scripting/examples/aux_cached.lua
@@ -1,7 +1,6 @@
 --[[ 
    example for getting cached aux function value
 --]]
--- luacheck: only 0
 
 
 local RATE_HZ = 10
@@ -11,7 +10,6 @@ local MAV_SEVERITY_INFO = 6
 
 local AUX_FUNCTION_NUM = 302
 
-local last_func_val = nil
 local last_aux_pos = nil
 
 function update()
diff --git a/libraries/AP_Scripting/examples/copy_userdata.lua b/libraries/AP_Scripting/examples/copy_userdata.lua
index 6e68c97406..5f186e3f10 100644
--- a/libraries/AP_Scripting/examples/copy_userdata.lua
+++ b/libraries/AP_Scripting/examples/copy_userdata.lua
@@ -1,7 +1,6 @@
 --[[
  An example of using the copy() method on userdata
 --]]
--- luacheck: only 0
 
 
 local loc1 = Location()
@@ -24,5 +23,5 @@ local v2 = v1:copy()
 v2:x(v2:x()+100)
 v2:y(v2:y()+300)
 
-local diff = v2 - v1
+diff = v2 - v1
 gcs:send_text(0,string.format("vdiff=(%.2f,%.2f)", diff:x(), diff:y()))
diff --git a/libraries/AP_Scripting/examples/opendog_demo.lua b/libraries/AP_Scripting/examples/opendog_demo.lua
index d518b95c6e..cefe8f1736 100644
--- a/libraries/AP_Scripting/examples/opendog_demo.lua
+++ b/libraries/AP_Scripting/examples/opendog_demo.lua
@@ -1,14 +1,9 @@
 -- demo of waving paw of opendog
--- luacheck: only 0
 
-local flipflop = true
-
-pwm = { 1500, 1500, 2000,
-        1500, 1500, 1000,
-        1500, 1500, 1500,
-        1500, 1500, 1500 }
-
-local angle = 0.0
+local pwm = { 1500, 1500, 2000,
+              1500, 1500, 1000,
+              1500, 1500, 1500,
+              1500, 1500, 1500 }
 
 function update()
    local t = 0.001 * millis():tofloat()
diff --git a/libraries/AP_Scripting/examples/param_get_set_test.lua b/libraries/AP_Scripting/examples/param_get_set_test.lua
index 07e84764cc..29baba29b6 100644
--- a/libraries/AP_Scripting/examples/param_get_set_test.lua
+++ b/libraries/AP_Scripting/examples/param_get_set_test.lua
@@ -1,5 +1,4 @@
 -- This script is a test of param set and get
--- luacheck: only 0
 
 local count = 0
 
@@ -21,7 +20,9 @@ local user_param = Parameter('SCR_USER1')
 -- this will error out for a bad parameter
 -- Parameter('FAKE_PARAM')
 local success, err = pcall(Parameter,'FAKE_PARAM')
-gcs:send_text(0, "Lua Caught Error: " .. err)
+if not success then
+  gcs:send_text(0, "Lua Caught Error: " .. err)
+end
 -- this allows this example to catch the otherwise fatal error
 -- not recommend if error is possible/expected, use separate construction and init
 
diff --git a/libraries/AP_Scripting/examples/rangefinder_test.lua b/libraries/AP_Scripting/examples/rangefinder_test.lua
index af5058d8a5..b6832bf54b 100644
--- a/libraries/AP_Scripting/examples/rangefinder_test.lua
+++ b/libraries/AP_Scripting/examples/rangefinder_test.lua
@@ -1,5 +1,4 @@
 -- This script checks RangeFinder
--- luacheck: only 0
 
 local rotation_downward = 25
 local rotation_forward = 0
@@ -8,7 +7,7 @@ function update()
   local sensor_count = rangefinder:num_sensors()
   gcs:send_text(0, string.format("%d rangefinder sensors found.", sensor_count))
 
-  for i = 0, rangefinder:num_sensors() do
+  for _ = 0, rangefinder:num_sensors() do
     if rangefinder:has_data_orient(rotation_downward) then
       info(rotation_downward)
     elseif rangefinder:has_data_orient(rotation_forward) then
diff --git a/libraries/AP_Scripting/examples/rover-SaveTurns.lua b/libraries/AP_Scripting/examples/rover-SaveTurns.lua
index 58cffa4833..9e530f2331 100644
--- a/libraries/AP_Scripting/examples/rover-SaveTurns.lua
+++ b/libraries/AP_Scripting/examples/rover-SaveTurns.lua
@@ -11,7 +11,6 @@ of a vehicle.  Use this script AT YOUR OWN RISK.
 
 LICENSE - GNU GPLv3 https://www.gnu.org/licenses/gpl-3.0.en.html
 ------------------------------------------------------------------------------]]
--- luacheck: only 0
 
 local SCRIPT_NAME = 'SaveTurns'
 
@@ -33,7 +32,6 @@ local WAYPOINT        = 16   -- waypoint command
 local MAV_SEVERITY_WARNING = 4
 local MAV_SEVERITY_INFO    = 6
 local MSG_NORMAL           = 1
-local MSG_DEBUG            = 2
 
 local RC_CHAN = rc:find_channel_for_option(RC_OPTION)
 local last_wp = Location()
diff --git a/libraries/AP_Scripting/examples/set-target-location.lua b/libraries/AP_Scripting/examples/set-target-location.lua
index d40ca3c4c1..b7c2776b5d 100644
--- a/libraries/AP_Scripting/examples/set-target-location.lua
+++ b/libraries/AP_Scripting/examples/set-target-location.lua
@@ -5,7 +5,6 @@
 --    a) switches to Guided mode
 --    b) sets the target location to be 10m above home
 --    c) switches the vehicle to land once it is within a couple of meters of home
--- luacheck: only 0
 
 local wp_radius = 2
 local target_alt_above_home = 10
diff --git a/libraries/AP_Scripting/examples/set_target_posvel_circle.lua b/libraries/AP_Scripting/examples/set_target_posvel_circle.lua
index 45c12a0ebc..87d4d95382 100644
--- a/libraries/AP_Scripting/examples/set_target_posvel_circle.lua
+++ b/libraries/AP_Scripting/examples/set_target_posvel_circle.lua
@@ -7,7 +7,6 @@
 --      2) switch to GUIDED mode 
 --      3) the vehilce will follow a circle in clockwise direction with increasing speed until ramp_up_time_s time has passed.
 --      4) switch out of and into the GUIDED mode any time to restart the trajectory from the start.
--- luacheck: only 0
 
 -- Edit these variables
 local rad_xy_m = 10.0   -- circle radius in xy plane in m
@@ -26,7 +25,7 @@ gcs:send_text(0,"Script started")
 gcs:send_text(0,"Trajectory period: " .. tostring(2 * math.rad(180) / omega_radps))
 
 function circle()
-    local cur_freq = 0
+    local cur_freq
     -- increase target speed lineary with time until ramp_up_time_s is reached
     if time <= ramp_up_time_s then 
         cur_freq = omega_radps*(time/ramp_up_time_s)^2
@@ -57,9 +56,7 @@ function update()
     if arming:is_armed() and vehicle:get_mode() == copter_guided_mode_num and -test_start_location:z()>=5 then
 
         -- calculate current position and velocity for circle trajectory
-        local target_pos = Vector3f()
-        local target_vel = Vector3f()
-        target_pos, target_vel = circle()
+        local target_pos, target_vel = circle()
 
         -- advance the time
         time = time + sampling_time_s
diff --git a/libraries/AP_Scripting/examples/terrain_warning.lua b/libraries/AP_Scripting/examples/terrain_warning.lua
index 4add211232..553804f35f 100644
--- a/libraries/AP_Scripting/examples/terrain_warning.lua
+++ b/libraries/AP_Scripting/examples/terrain_warning.lua
@@ -1,5 +1,4 @@
 -- height above terrain warning script
--- luacheck: only 0
 
 -- min altitude above terrain, script will warn if lower than this
 local terrain_min_alt = 20
@@ -15,7 +14,6 @@ local warn_ms = 10000
 
 
 local height_threshold_passed = false
-local last_warn = 0
 function update()
 
   if not arming:is_armed() then
diff --git a/libraries/AP_Scripting/examples/wp_test.lua b/libraries/AP_Scripting/examples/wp_test.lua
index 7f1e5e889b..a52d483343 100644
--- a/libraries/AP_Scripting/examples/wp_test.lua
+++ b/libraries/AP_Scripting/examples/wp_test.lua
@@ -1,12 +1,9 @@
 -- Example script for accessing waypoint info
--- luacheck: only 0
 
 local wp_index
 local wp_distance
 local wp_bearing
 local wp_error
-local wp_max_distance = 0
-local last_log_ms = millis()
 
 
 function on_wp_change(index, distance)