npm install --global posthtml-cli

$ posthtml --help

    Usage
    posthtml [-o output-file/directory|-r] [-i input-file/directory] [--config|-c path/to/file/config] [--use|-u plugin]

    Options
    --config,  -c Path to JSON file                  [string]
    --output,  -o Output html file/folder result     [required]
    --input,   -i Input html file/folder             [required]
    --use,     -u Posthtml plugin name               [string]
    --replace, -r Replace input file(s)              [boolean]
    --help,    -h Show help                          [boolean]
    --version, -v Show version number                [boolean]    

{
    "name": "my project",
    "dependencies": {
        "posthtml-bem": "^0.2.2",
        "posthtml-each": "^1.0.1",
        "posthtml-include": "^1.0.2"
    },
    "devDependencies": {
        "posthtml-style-to-file": "^0.1.1"
    },
    "posthtml": {
        "bem": {
            "elemPrefix": "__",
            "modPrefix": "-",
            "modDlmtr": "--"
        },
        "include": {
            "root": "./",
            "encoding": "utf-8"
        },
        "styleToFile": {
            "path": "./dist/style.css"
        }
    }
}

module.exports = {
    bem: {
        elemPrefix: '__',
        modPrefix: '-',
        modDlmtr: '--'
    },
    include: {
        root: './',
        encoding: 'utf-8'
    },
    styleToFile: {
        path: './dist/style.css'
    }
}

{
    "bem": {
        "elemPrefix": "__",
        "modPrefix": "-",
        "modDlmtr": "--"
    },
    "include": {
        "root": "./",
        "encoding": "utf-8"
    },
    "styleToFile": {
        "path": "./dist/style.css"
    }
}

$ posthtml -o output.html -i input.html

$ posthtml -o output.html -i input.html -c posthtml.json

$ posthtml -o output.html -i input.html -c posthtml.js

$ posthtml 
    -o output.html 
    -i input.html 
    -c config.json 
    -u posthtml-bem 
    --posthtml-bem.elemPrefix __
    --posthtml-bem.elemMod _
    -u posthtml-css-modules
    --posthtml-css-modules path/to/json
    -u posthtml-custom-elements

$ posthtml -o outputFolder/ -i inputFolder/*.html

$ posthtml -o outputFolder/ -i inputFolder/**/*.html

$ posthtml -i input.html -r

$ posthtml -i inputFolder/*.html -r