diff --git a/wled b/wled
index 260c8be..946d282 100755
--- a/wled
+++ b/wled
@@ -10,22 +10,22 @@ CURL_FLAGS="--silent --show-error --fail --ipv4 --max-filesize 64K"
 
 print_usage() {
     echo "Usage: $0 f(nordcenter)|w(ohnzimmer) on|off|1-17|list"
+    echo "       $0 f(nordcenter)|w(ohnzimmer) b(rightness) [1-255]"
 }
 
-if test $# -ne 2; then
-    print_usage
-    exit 0
-fi
-
 # Parse host argument.
 case "$1" in
+    ""|-h|--h) # Missing host parameter.
+        print_usage
+        exit 0
+    ;;
     f|fnordcenter)
         wled_host='wled-fnordcenter.local'
     ;;
     w|wohnzimmer)
         wled_host='wled-wohnzimmer.local'
     ;;
-    *)
+    *) # Unknown host parameter.
         echo "Error: unknown host \"$1\"." >&2
         print_usage
         exit 1
@@ -34,16 +34,32 @@ esac
 
 # Parse and execute command argument.
 case "$2" in
-    on)
+    on) # Switch on.
         api_resp=$(curl $CURL_FLAGS --json '{"on":true}' "http://$wled_host/json")
     ;;
-    off)
+    off) # Switch off.
         api_resp=$(curl $CURL_FLAGS --json '{"on":false}' "http://$wled_host/json")
     ;;
-    [1-9]|[1-9][0-7])
+    b|brightness) # Set brightness.
+        if test -z "$3"; then
+            echo "Error: missing parameter for brightness." >&2
+            exit 1
+        fi
+        # Try to convert 3rd parameter to an integer between 1 an 255.
+        bright=$(printf '%u' "$3" 2>/dev/null)
+        if test $? -gt 0; then # Conversion failed.
+            echo "Error: unable to parse parameter for brightness." >&2
+            exit 1
+        elif test "$bright" -lt 1 -o "$bright" -gt 255; then
+            echo "Error: parameter for brightness is out of range." >&2
+            exit 1
+        fi
+        api_resp=$(curl $CURL_FLAGS --json "{'bri':$bright}" "http://$wled_host/json")
+    ;;
+    [1-9]|1[0-7]) # Switch to preset.
         api_resp=$(curl $CURL_FLAGS --json "{'on':true,'ps':$2}" "http://$wled_host/json")
     ;;
-    l|list)
+    l|list) # List presets.
         echo "Presets on $wled_host:"
         curl $CURL_FLAGS "http://$wled_host/presets.json" | \
             # Split into lines - one line per preset. Append final newline.
@@ -52,11 +68,16 @@ case "$2" in
             sed --sandbox -n 's/^"\(1\?[0-9]\)":.*"n":"\([[:print:]]*\)".*$/\1: \2/p'
         exit $?
     ;;
-    dump)
+    dump) # Dump JSON response from API.
         curl $CURL_FLAGS -w '\n' "http://$wled_host/json"
         exit 0
     ;;
-    *)
+    "") # Missing command.
+        echo "Error: missing command." >&2
+        print_usage
+        exit 1
+    ;;
+    *) # Unknown command.
         echo "Error: unknown command \"$2\"." >&2
         print_usage
         exit 1
@@ -65,7 +86,7 @@ esac
 
 curl_exit=$?
 if test $curl_exit -ne 0; then
-    echo "Error: curl exited with exit code $curl_exit."
+    echo "Error: curl exited with exit code $curl_exit." >&2
     exit 1
 fi