diff --git a/dim b/dim
index ece4a7d..845f4a4 100755
--- a/dim
+++ b/dim
@@ -6,7 +6,7 @@
 #James B. Ackman 2019-02-06T15:55:20-08:00
 
 #check kernel backlight driver names on your machine: `ls -l /sys/class/backlight/*`
-#then set following var, e.g. acpi_video0 or intel_backlight
+#then set following var, e.g. acpi_video0 nv_backlight or intel_backlight
 backlightDriver="intel_backlight"
 set -e #exit if an error
 percentValue=$1
diff --git a/hdmi.sh b/hdmi.sh
index a8842c2..3a0fd10 100755
--- a/hdmi.sh
+++ b/hdmi.sh
@@ -1,7 +1,19 @@
 #!/bin/bash
-#setup external hdmi display if connected, else ensure the display is off
+if [ "$1" == "-h" ] ; then
+    echo "
+          hdmi - setup external display if connected, else ensure the display is off
+               - run 'xrandr' to see display interface names for input
+    
+              Usage: hdmi.sh 
+                     hdmi.sh DP1 
+    "
+    exit 0
+fi
+
+set -e
+
 intern=eDP1
-extern=HDMI1
+extern=${1:-HDMI1}
 
 if xrandr | grep "$extern connected"; then
     xrandr --output "$intern" --auto --output "$extern" --auto --right-of "$intern"