correct exit code (https://github.com/ImageMagick/ImageMagick/issues/6744)

MagickWand/compare.c

@@ -292,7 +292,12 @@ WandExport MagickBooleanType CompareImagesCommand(ImageInfo *image_info,
         }
     }
   if (argc < 3)
-    return(CompareUsage());
+    {
+      (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+        "MissingArgument","%s","");
+      (void) CompareUsage();
+      return(MagickFalse);
+    }
   difference_image=NewImageList();
   similarity_image=NewImageList();
   dissimilarity_threshold=DefaultDissimilarityThreshold;

MagickWand/composite.c

@@ -488,7 +488,12 @@ WandExport MagickBooleanType CompositeImageCommand(ImageInfo *image_info,
         }
     }
   if (argc < 4)
-    return(CompositeUsage());
+    {
+      (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+        "MissingArgument","%s","");
+      (void) CompositeUsage();
+      return(MagickFalse);
+    }
   GetCompositeOptions(image_info,&composite_options);
   filename=(char *) NULL;
   format="%w,%h,%m";

MagickWand/conjure.c

@@ -168,7 +168,12 @@ WandExport MagickBooleanType ConjureImageCommand(ImageInfo *image_info,
   if (IsEventLogging() != MagickFalse)
     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
   if (argc < 2)
-    return(ConjureUsage());
+    {
+      (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+        "MissingArgument","%s","");
+      (void) ConjureUsage();
+      return(MagickFalse);
+    }
   image=NewImageList();
   number_images=0;
   option=(char *) NULL;

MagickWand/convert.c

@@ -558,7 +558,12 @@ WandExport MagickBooleanType ConvertImageCommand(ImageInfo *image_info,
         }
     }
   if (argc < 3)
-    return(ConvertUsage());
+    {
+      (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+        "MissingArgument","%s","");
+      (void) ConvertUsage();
+      return(MagickFalse);
+    }
   filename=(char *) NULL;
   format="%w,%h,%m";
   j=1;

MagickWand/identify.c

@@ -241,7 +241,12 @@ WandExport MagickBooleanType IdentifyImageCommand(ImageInfo *image_info,
         }
     }
   if (argc < 2)
-    return(IdentifyUsage());
+    {
+      (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+        "MissingArgument","%s","");
+      (void) IdentifyUsage();
+      return(MagickFalse);
+    }
   count=0;
   format=NULL;
   j=1;

MagickWand/mogrify.c

@@ -3789,7 +3789,12 @@ WandExport MagickBooleanType MogrifyImageCommand(ImageInfo *image_info,
         }
     }
   if (argc < 2)
-    return(MogrifyUsage());
+    {
+      (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+        "MissingArgument","%s","");
+      (void) MogrifyUsage();
+      return(MagickFalse);
+    }
   format=(char *) NULL;
   path=(char *) NULL;
   global_colormap=MagickFalse;

MagickWand/montage.c

@@ -327,7 +327,12 @@ WandExport MagickBooleanType MontageImageCommand(ImageInfo *image_info,
         }
     }
   if (argc < 3)
-    return(MontageUsage());
+    {
+      (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+        "MissingArgument","%s","");
+      (void) MontgagUsage();
+      return(MagickFalse);
+    }
   format="%w,%h,%m";
   first_scene=0;
   j=1;

MagickWand/stream.c

@@ -224,7 +224,12 @@ WandExport MagickBooleanType StreamImageCommand(ImageInfo *image_info,
         }
     }
   if (argc < 3)
-    return(StreamUsage());
+    {
+      (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+        "MissingArgument","%s","");
+      (void) StreamUsage();
+      return(MagickFalse);
+    }
   format="%w,%h,%m";
   (void) format;
   j=1;