Create a cssbuilder.config.json under the input folder. The content is an array of settings.

For example, compile a.less to a.css:

[
    {
        "src": "a.less",
        "output": "a.css" 
    }
]

output is optional. The following setting is the same as the above:

[
    {
        "src": "a.less"
    }
]

src support glob patter, for example, compile all *.less files, and output to out folder:

[
    {
        "src": "**/*.less",
        "output": "out/"
    }
]

src can be array of strings, for example, compile all *.less under folder b and folder c. Output to out folder:

[
    {
        "src": [ "a/**/*.less", "b/**/*.less" ],
        "output": "out/"
    }
]

If you want to combine all source files into one file, you can set output as a single file. For example:

[
    {
        "src": [ "a/**/*.less", "b/**/*.less" ],
        "output": "out/overall.css"
    }
]

It will compile all *.less files under folder a and folder b. Results will be combined and write to out/overall.css.

If you want to generate compressed css file, you can set minify to true. For example:

[
    {
        "src": "a.less",
        "output": "a.css",
        "minify": true
    }
]

Note:

1. Configuration file is not required. If it is not existed, all supported files (.less/.sass/*.scss) will be processed. Use -r if you want to process recursively.
2. If configuration file is existed, -r option will be ignored.
3. If output is not ended with .css, will be treated as an output folder.
4. If output is a relative path, it is related to the folder of the configuration file not the folder of the input file.
5. Folder structure won't be kept. If input is a/a.less, b/b.less, and output is out, the final output file will be out/a.css and out/b.css.