cannot Compile SASS into CSS but mapping looks alright

Solution for cannot Compile SASS into CSS but mapping looks alright
is Given Below:

I have sass installed globally in the terminal. npm install sass -g. I have a sass file in source folder
$grey: #444; $red: rgb(250, 0, 0);
To compile the sass into css from source folder to css folder. I type:

@sass –watch source/style.scss css/style.css
The result in the terminal:
comile sass

The and style.css generated in css folder.
The result is have output {"version":3,"sourceRoot":"","sources":[],"names":[],"mappings":"","file":"style.css"}
and The output in style.css have

/*# */

So, I can see mapping looks alright.But where is my css file output. I need some pointer.

I have installed sass globally using npm install sass -g and I was compiling
sass file using @sass --watch source/style.scss css/style.css. That was all right with sass file declaring variables $grey: #444; $red: rgb(250, 0, 0);. One thing I missed was adding a colon (:) between arguments of sass –watch command, like @sass --watch source/style.css:css/style.css which is usually not required if it was files only.

When I compile the file, it generated the files style.css within folder css.
The mappingURL output was shown because I was not using those variables. Which I added later as:

body {
 margin: 0;
 padding: 0;
 background-color: $grey;
 color: $red;
Then then css file was compiling sass file to css. That was it.