Revised exit status generation.

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] set brightness
+
+exit status:
+    0   no failure
+    1   operating error
+    2   child command error
+    4   unexpected API response"
 }
 
 curl_fetch() {
@@ -54,6 +64,7 @@ active_preset() {
 arg_inst="$1"
 arg_cmnd="$2"
 arg_param="$3"
+exit_code=0
 
 # Clear positional arguments.
 set --
@@ -132,6 +143,7 @@ for wled_host; do
                 # Prepend description and mark active preset.
                 sed --sandbox -e "1i\\Presets on $wled_host:" \
                               -e "s/^ \?$active_ps:.*/& */"
+
         ;;
         "") # Missing command.
             echo "Error: missing command." >&2
@@ -145,15 +157,19 @@ for wled_host; 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
 done
 
+exit $exit_code
+