A simple javascript script to help you take the **awk** main loop

awk-loop.js

// This simple javascript script what @yorkie write is just show you my
// knowledge on awk main loop.

var fs = require('fs');
var lines = fs.readFileSync('your awk file path').toString('utf8').split('\r\n');
var rules = [
  // Here you define the rule for input  
]

lines
  .filter(function(line) {
    return rules.filter(function (rule){
      // match rule for this line and returns result
      return rule.match(line);
   }
  })
  .filter(function(res) {
    // if result isn't an array or its length is less than zero(0), drop it.
    return Array.isArray(res) && res.length > 0;
  });

// Then, the processing of awk main loop just is:
// 1. load the rules from you specified awk script
// 2. load the input from file or shell and read it line by line
// 3. for one line, it apply all the rules loaded from the step 1, and selected the proper line.
// 4. just output the result that passed the below 3 steps.

You could visit http://docstore.mik.ua/orelly/unix2.1/sedawk/ch07_04.htm to get more details about AWK programming language, and sed the other text-processing tool in *nix.