Print brightness if -b is called without parameter.

README.md

@@ -13,7 +13,7 @@ Switch between presets 1 to 17 or list available presets:
 
 `$ wled -f|-w|-a [1-17|l(ist)]`
 
-Change brightness:
+Display or change brightness:
 
 `$ wled -f|-w|-a -b [1-255]`
 

wled

@@ -10,6 +10,10 @@ NAME="wled.sh"
 COMMAND="wled"
 VERSION="0.1.2"
 
+# Make the exit status of command pipelines the status of the last command
+# with non-zero exit status - if supported by this shell.
+(set -o pipefail 2>/dev/null) && set -o pipefail
+
 print_usage() {
     echo "\
 Usage: $COMMAND -f(norcenter)|-w(wohnzimmer)|-a(ll) [on|off]
@@ -29,7 +33,13 @@ commands:
     on|off                  switch on/off
     [1-17]                  switch preset
     l, list                 list presets
-    -b,--brightness [1-255] set brightness"
+    -b,--brightness [1-255] get or set brightness
+
+exit status:
+    0   no failure
+    1   operating error
+    2   child command error
+    4   unexpected API response"
 }
 
 curl_fetch() {
@@ -51,9 +61,16 @@ active_preset() {
         sed -n 's/.*"ps"[[:space:]]*:[[:space:]]*\(1\?[0-9]\).*/\1/p'
 }
 
+current_brightness() {
+    # Find current brightness.
+    curl_fetch "http://$1/json" | \
+        sed -n 's/.*"state"[[:space:]]*:[[:space:]]*{[^}]*"bri"[[:space:]]*:[[:space:]]*\([0-9]\{1,3\}\).*/\1/p'
+}
+
 arg_inst="$1"
 arg_cmnd="$2"
 arg_param="$3"
+exit_code=0
 
 # Clear positional arguments.
 set --
@@ -86,37 +103,39 @@ case "$arg_inst" in
 esac
 
 # Parse and execute command argument against given instances.
-while test $# -gt 0; do
+for wled_host; do
     case "$arg_cmnd" in
         on) # Switch on.
-            api_resp=$(curl_send '{"on":true}' "http://$1/json")
+            api_resp=$(curl_send '{"on":true}' "http://$wled_host/json")
         ;;
         off) # Switch off.
-            api_resp=$(curl_send '{"on":false}' "http://$1/json")
+            api_resp=$(curl_send '{"on":false}' "http://$wled_host/json")
         ;;
         -b|--brightness) # Set brightness.
             if test -z "$arg_param"; then
-                echo "Error: missing parameter for brightness." >&2
-                exit 1
+                # No parameter given. Print current brightness.
+                echo "Current brightness of $wled_host:"
+                current_brightness "$wled_host"
+            else
+                # Try to convert 3rd parameter to an integer between 1 an 255.
+                bright=$(printf '%u' "$arg_param" 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_send "{'bri':$bright}" "http://$wled_host/json")
             fi
-            # Try to convert 3rd parameter to an integer between 1 an 255.
-            bright=$(printf '%u' "$arg_param" 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_send "{'bri':$bright}" "http://$1/json")
         ;;
         [1-9]|1[0-7]) # Switch to preset.
-            api_resp=$(curl_send "{'ps':$arg_cmnd}" "http://$1/json")
+            api_resp=$(curl_send "{'ps':$arg_cmnd}" "http://$wled_host/json")
         ;;
         l|list) # List presets.
             printf "loading ...\r"
-            active_ps=$(active_preset "$1")
-            curl_fetch "http://$1/presets.json" | \
+            active_ps=$(active_preset "$wled_host")
+            curl_fetch "http://$wled_host/presets.json" | \
                 # Split into lines - one line per preset.
                 sed --sandbox 's/"1\?[0-9]"[[:space:]]*:/\n&/g' | \
                 # Extract number and name of every preset. Right-align numbers.
@@ -130,8 +149,9 @@ while test $# -gt 0; do
                 # Sort.
                 sort -b -n | \
                 # Prepend description and mark active preset.
-                sed --sandbox -e "1i\\Presets on $1:" \
+                sed --sandbox -e "1i\\Presets on $wled_host:" \
                               -e "s/^ \?$active_ps:.*/& */"
+
         ;;
         "") # Missing command.
             echo "Error: missing command." >&2
@@ -145,17 +165,19 @@ while test $# -gt 0; do
         ;;
     esac
 
-    # Check curl exit status
-    curl_exit=$?
-    if test $curl_exit -ne 0; then
-        echo "Error: curl exited with exit code $curl_exit." >&2
+    # Check curl (or maybe sed) exit status
+    child_exit=$?
+    if test $child_exit -ne 0; then
+        echo "Error: curl or sed exited with exit code $child_exit." >&2
+        exit_code=$((exit_code|2))
     fi
 
-    # Check API responce.
+    # Check API response.
     if test -n "$api_resp" && echo "$api_resp" | grep -qv '{\s*"success"\s*:\s*true\s*}'; then
-        echo "Warning: unexpected responce from WLED API." >&2
+        echo "Warning: unexpected response from WLED API." >&2
+        exit_code=$((exit_code|4))
     fi
-
-    shift
 done
 
+exit $exit_code
+