sed.js

sed.js

var fs = require('fs');
var util = require('util');

function main() {

  var args = process.argv.slice(2);

  if (args.length === 3) {

    var regex = eval(args[0]);
    var replace = args[1].replace(/~n/g, "\n").replace(/%(\d+)/g, '$$$1').replace(/%%/g, '%');
    var file = args[2];

    if (regex instanceof RegExp) {

      if (fs.existsSync(file)) {

        if (fs.statSync(file).isFile()) {

          var buf = fs.readFileSync(file, 'utf8');
          var modified = buf.replace(regex, replace);

          if (modified != buf) {
            fs.writeFileSync(file, modified, 'utf8');
          }

        }

      } else {

        console.log(util.format("\nFile not found: %s\n", file));
        process.exit();

      }

    } else {

      console.log("\nNot a regular expression: %s\n", args[0]);
      process.exit();

    }

  } else {

    console.log("\nUsage: sed.js <regex> <replace> <file>\n");
    process.exit();

  }

}

main();