cat.js

const fs = require('fs')
const readline = require('readline');
const os = require("os");

var args = [...process.argv]

if (args.length >= 3 && args[2].indexOf('.') > -1) {

    args.shift()
    args.shift();

    const isCopy = args.includes('-c')
    const isLine = args.includes('-l')

    let lineNumber = 1
    let lines = ""

    const path = args[0].replace(/\\/g, "\\\\");
    const rl = readline.createInterface({
        input: fs.createReadStream(path, "utf8"),
        output: process.stdout,
        terminal: false
    });
    rl.on('line', (line) => {

        if (isLine) {
            console.log(`${lineNumber}: ${line}`)
            lineNumber++;
        } else {

            console.log(line);
        }
        if (isCopy) {
            const temp = line + os.EOL
            lines += temp;


        }
    });
    rl.on('close', () => {
        if (isCopy) {

            require('child_process').spawn('clip').stdin.end(lines);
            console.log("copied...");
        }
    })
} else {
    console.error("no path found ....    ")
    console.log("try cat <filename>")
    console.log("-c for copy file conent")
    console.log("-l to show line number")
    process.exit(1)
}