old_contents: "use strict";
  
  const net = require("net");
  const os = require("os");
  const execa = require("execa");
  
  const args = {
    v4: ["-4", "r"],
    v6: ["-6", "r"],
  };
  
  const parse = (stdout, family) => {
    let result;
  
    (stdout || "").trim().split("\n").some(line => {
      const results = /default( via .+?)?( dev .+?)( |$)/.exec(line) || [];
      const gateway = (results[1] || "").substring(5);
      const iface = (results[2] || "").substring(5);
      if (gateway && net.isIP(gateway)) { // default via 1.2.3.4 dev en0
        result = {gateway, interface: (iface ? iface : null)};
        return true;
      } else if (iface && !gateway) { // default via dev en0
        const interfaces = os.networkInterfaces();
        const addresses = interfaces[iface];
        if (!addresses || !addresses.length) return;
  
        addresses.some(addr => {
          if (addr.family.substring(2) === family && net.isIP(addr.address)) {
            result = {gateway: addr.address, interface: (iface ? iface : null)};
            return true;
          }
        });
      }
    });
  
    if (!result) {
      throw new Error("Unable to determine default gateway");
    }
  
    return result;
  };
  
  const promise = async family => {
    const {stdout} = await execa("netstat", args[family]);
    return parse(stdout, family);
  };
  
  const sync = family => {
    const {stdout} = execa.sync("ip", args[family]);
    return parse(stdout, family);
  };
  
  module.exports.v4 = () => promise("v4");
  module.exports.v6 = () => promise("v6");
  
  module.exports.v4.sync = () => sync("v4");
  module.exports.v6.sync = () => sync("v6");
  
new_contents: "use strict";
  
  const net = require("net");
  const os = require("os");
  const execa = require("execa");
  
  const args = {
    v4: ["-4", "r"],
    v6: ["-6", "r"],
  };
  
  const parse = (stdout, family) => {
    let result;
  
    (stdout || "").trim().split("\n").some(line => {
      const results = /default( via .+?)?( dev .+?)( |$)/.exec(line) || [];
      const gateway = (results[1] || "").substring(5);
      const iface = (results[2] || "").substring(5);
      if (gateway && net.isIP(gateway)) { // default via 1.2.3.4 dev en0
        result = {gateway, interface: (iface ? iface : null)};
        return true;
      } else if (iface && !gateway) { // default via dev en0
        const interfaces = os.networkInterfaces();
        const addresses = interfaces[iface];
        if (!addresses || !addresses.length) return;
  
        addresses.some(addr => {
          if (addr.family.substring(2) === family && net.isIP(addr.address)) {
            result = {gateway: addr.address, interface: (iface ? iface : null)};
            return true;
          }
        });
      }
    });
  
    if (!result) {
      throw new Error("Unable to determine default gateway");
    }
  
    return result;
  };
  
  const promise = async family => {
    const {stdout} = await execa("ip", args[family]);
    return parse(stdout, family);
  };
  
  const sync = family => {
    const {stdout} = execa.sync("ip", args[family]);
    return parse(stdout, family);
  };
  
  module.exports.v4 = () => promise("v4");
  module.exports.v6 = () => promise("v6");
  
  module.exports.v4.sync = () => sync("v4");
  module.exports.v6.sync = () => sync("v6");
  
subject: fix linux typo