diff --git a/.prettierrc.js b/.prettierrc.js
new file mode 100644
index 0000000..9851b79
--- /dev/null
+++ b/.prettierrc.js
@@ -0,0 +1,6 @@
+module.exports = {
+  tabWidth: 2,
+  singleQuote: true,
+  printWidth: 120,
+  trailingComma: 'none',
+};
diff --git a/README.md b/README.md
index b2728ee..1eef59f 100644
--- a/README.md
+++ b/README.md
@@ -67,7 +67,8 @@ Description:
      once resources are available. ex: wait-on f1 && NEXT_CMD
 
      resources types are defined by their prefix, if no prefix is
-     present, the resource is assumed to be of type 'file'
+     present, the resource is assumed to be of type 'file'. Resources
+     can also be provided in the config file.
 
      resource prefixes are:
 
@@ -86,7 +87,7 @@ Standard Options:
 
  -c, --config
 
-  js or json config file, useful for http(s) options
+  js or json config file, useful for http(s) options and resources
 
  -d, --delay
 
@@ -155,7 +156,7 @@ var opts = {
     'tcp:foo.com:8000',
     'socket:/my/sock',
     'http://unix:/my/sock:/my/url',
-    'http-get://unix:/my/sock:/my/url',
+    'http-get://unix:/my/sock:/my/url'
   ],
   delay: 1000, // initial delay in ms, default 0
   interval: 100, // poll interval in ms, default 250ms
@@ -188,16 +189,16 @@ var opts = {
   } */,
   auth: {
     user: 'theuser', // or username
-    pass: 'thepassword', // or password
+    pass: 'thepassword' // or password
   },
   strictSSL: false,
   followRedirect: true,
   headers: {
-    'x-custom': 'headers',
+    'x-custom': 'headers'
   },
   validateStatus: function (status) {
     return status >= 200 && status < 300; // default if not provided
-  },
+  }
 };
 
 // Usage with callback function
@@ -232,6 +233,7 @@ waitOn(opts, [cb]) - function which triggers resource checks
 - opts.delay - optional initial delay in ms, default 0
 - opts.interval - optional poll resource interval in ms, default 250ms
 - opts.log - optional flag which outputs to stdout, remaining resources waited on and when complete or errored
+- opts.resources - optional array of string resources to wait for if none are specified via command line
 - opts.reverse - optional flag to reverse operation so checks are for resources being NOT available, default false
 - opts.simultaneous - optional count to limit concurrent connections per resource at a time, setting to 1 waits for previous connection to succeed, fail, or timeout before sending another, default infinity
 - opts.timeout - optional timeout in ms, default Infinity. Aborts with error.
diff --git a/bin/wait-on b/bin/wait-on
index 578f37b..0670fba 100755
--- a/bin/wait-on
+++ b/bin/wait-on
@@ -18,13 +18,16 @@ const minimistOpts = {
     t: 'timeout',
     v: 'verbose',
     w: 'window',
-    h: 'help',
-  },
+    h: 'help'
+  }
 };
 
 const argv = minimist(process.argv.slice(2), minimistOpts);
+// if a js/json configuration file is provided require it
+const configOpts = argv.config ? require(path.resolve(argv.config)) : {};
+const hasResources = argv._.length || (configOpts.resources && configOpts.resources.length);
 
-if (argv.help || !argv._.length) {
+if (argv.help || !hasResources) {
   // help
   fs.createReadStream(path.join(__dirname, '/usage.txt'))
     .pipe(process.stdout)
@@ -32,19 +35,14 @@ if (argv.help || !argv._.length) {
       process.exit(1);
     });
 } else {
-  let opts = {};
-
-  // if a js/json configuration file is provided require it
-  const configFile = argv.config;
-  if (configFile) {
-    opts = require(path.resolve(configFile));
+  // if resources are present in the command line then they take
+  // precedence over those in the config file.
+  if (argv._.length) {
+    configOpts.resources = argv._;
   }
 
-  // add in the resources listed on the command line
-  opts.resources = argv._;
-
   // now check for specific options and set those
-  opts = [
+  const opts = [
     'delay',
     'httpTimeout',
     'interval',
@@ -54,13 +52,13 @@ if (argv.help || !argv._.length) {
     'timeout',
     'tcpTimeout',
     'verbose',
-    'window',
+    'window'
   ].reduce(function (accum, x) {
     if (argv[x]) {
       accum[x] = argv[x];
     }
     return accum;
-  }, opts);
+  }, configOpts);
 
   waitOn(opts, function (err) {
     if (err) {
diff --git a/exampleConfig.js b/exampleConfig.js
index 924d257..c0f7020 100644
--- a/exampleConfig.js
+++ b/exampleConfig.js
@@ -13,11 +13,13 @@ module.exports = {
   passphrase: 'yourpassphrase',
   auth: {
     user: 'yourusername',
-    pass: 'yourpassword',
+    pass: 'yourpassword'
   },
   strictSSL: false,
   followRedirect: false,
   headers: {
-    'x-custom': 'headers',
+    'x-custom': 'headers'
   },
+  // optional default resources if not specified in command args
+  resources: ['http://foo/bar', 'http://cat/dog']
 };
diff --git a/lib/wait-on.js b/lib/wait-on.js
index 14de64b..43f5ab8 100644
--- a/lib/wait-on.js
+++ b/lib/wait-on.js
@@ -46,11 +46,11 @@ const WAIT_ON_SCHEMA = Joi.object({
   proxy: [Joi.boolean(), Joi.object()],
   auth: Joi.object({
     username: Joi.string(),
-    password: Joi.string(),
+    password: Joi.string()
   }),
   strictSSL: Joi.boolean().default(false),
   followRedirect: Joi.boolean().default(true), // HTTP 3XX responses
-  headers: Joi.object(),
+  headers: Joi.object()
 });
 
 /**
@@ -112,7 +112,7 @@ function waitOnImpl(opts, cbFunc) {
     ...validResult.value, // use defaults
     // window needs to be at least interval
     ...(validResult.value.window < validResult.value.interval ? { window: validResult.value.interval } : {}),
-    ...(validResult.value.verbose ? { log: true } : {}), // if debug logging then normal log is also enabled
+    ...(validResult.value.verbose ? { log: true } : {}) // if debug logging then normal log is also enabled
   };
 
   const { resources, log: shouldLog, timeout, verbose, reverse } = validatedOpts;
@@ -125,10 +125,14 @@ function waitOnImpl(opts, cbFunc) {
   let lastResourcesState = resources; // the last state we had recorded
 
   const timeoutError$ =
-    timeout !== Infinity ? timer(timeout).pipe(mergeMap(() => {
-      const resourcesWaitingFor = determineRemainingResources(resources, lastResourcesState).join(', ')
-      return throwError(Error(`${TIMEOUT_ERR_MSG}: ${resourcesWaitingFor}`))
-    })) : NEVER;
+    timeout !== Infinity
+      ? timer(timeout).pipe(
+          mergeMap(() => {
+            const resourcesWaitingFor = determineRemainingResources(resources, lastResourcesState).join(', ');
+            return throwError(Error(`${TIMEOUT_ERR_MSG}: ${resourcesWaitingFor}`));
+          })
+        )
+      : NEVER;
 
   function cleanup(err) {
     if (err) {
@@ -159,7 +163,7 @@ function waitOnImpl(opts, cbFunc) {
         logWaitingForWDeps(resourceStates);
       },
       error: cleanup,
-      complete: cleanup,
+      complete: cleanup
     });
 }
 
@@ -270,7 +274,7 @@ function createHTTP$({ validatedOpts, output }, resource) {
     proxy,
     reverse,
     simultaneous,
-    strictSSL: rejectUnauthorized,
+    strictSSL: rejectUnauthorized
   } = validatedOpts;
   const method = HTTP_GET_RE.test(resource) ? 'get' : 'head';
   const url = resource.replace('-get:', ':');
@@ -283,13 +287,13 @@ function createHTTP$({ validatedOpts, output }, resource) {
     ...pick(['auth', 'headers', 'validateStatus'], validatedOpts),
     httpsAgent: new https.Agent({
       rejectUnauthorized,
-      ...pick(['ca', 'cert', 'key', 'passphrase'], validatedOpts),
+      ...pick(['ca', 'cert', 'key', 'passphrase'], validatedOpts)
     }),
     ...(followRedirect ? {} : { maxRedirects: 0 }), // defaults to 5 (enabled)
     proxy, // can be undefined, false, or object
     ...(timeout && { timeout }),
     ...urlSocketOptions,
-    method,
+    method
     // by default it provides full response object
     // validStatus is 2xx unless followRedirect is true (default)
   };
diff --git a/test/api.mocha.js b/test/api.mocha.js
index 31f3b9b..86cb5e3 100644
--- a/test/api.mocha.js
+++ b/test/api.mocha.js
@@ -31,7 +31,7 @@ describe('api', function () {
     temp.mkdir({}, function (err, dirPath) {
       if (err) return done(err);
       const opts = {
-        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar/deeper/deep/yet')],
+        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar/deeper/deep/yet')]
       };
       fs.writeFileSync(opts.resources[0], 'data1');
       mkdirp.sync(path.dirname(opts.resources[1]));
@@ -47,7 +47,7 @@ describe('api', function () {
     temp.mkdir({}, function (err, dirPath) {
       if (err) return done(err);
       const opts = {
-        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar/deeper/deep/yet')],
+        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar/deeper/deep/yet')]
       };
 
       setTimeout(function () {
@@ -65,7 +65,7 @@ describe('api', function () {
 
   it('should succeed when http resources are become available later', function (done) {
     const opts = {
-      resources: ['http://localhost:3000', 'http://localhost:3000/foo'],
+      resources: ['http://localhost:3000', 'http://localhost:3000/foo']
     };
 
     setTimeout(function () {
@@ -86,7 +86,7 @@ describe('api', function () {
       resources: ['http://localhost:3000'],
       validateStatus: function (status) {
         return status === 401 || (status >= 200 && status < 300);
-      },
+      }
     };
 
     setTimeout(function () {
@@ -106,7 +106,7 @@ describe('api', function () {
   it('should succeed when http resource become available later via redirect', function (done) {
     const opts = {
       // followRedirect: true // default is true
-      resources: ['http://localhost:3000'],
+      resources: ['http://localhost:3000']
     };
 
     setTimeout(function () {
@@ -128,7 +128,7 @@ describe('api', function () {
 
   it('should succeed when http GET resources become available later', function (done) {
     const opts = {
-      resources: ['http-get://localhost:3011', 'http-get://localhost:3011/foo'],
+      resources: ['http-get://localhost:3011', 'http-get://localhost:3011/foo']
     };
 
     setTimeout(function () {
@@ -147,7 +147,7 @@ describe('api', function () {
   it('should succeed when http GET resource become available later via redirect', function (done) {
     const opts = {
       // followRedirect: true, // default is true
-      resources: ['http-get://localhost:3000'],
+      resources: ['http-get://localhost:3000']
     };
 
     setTimeout(function () {
@@ -197,7 +197,7 @@ describe('api', function () {
 
   it('should succeed when a service is listening to tcp port', function (done) {
     const opts = {
-      resources: ['tcp:localhost:3001', 'tcp:3001'],
+      resources: ['tcp:localhost:3001', 'tcp:3001']
     };
 
     setTimeout(function () {
@@ -219,7 +219,7 @@ describe('api', function () {
       if (err) return done(err);
       socketPath = path.resolve(dirPath, 'sock');
       const opts = {
-        resources: ['socket:' + socketPath],
+        resources: ['socket:' + socketPath]
       };
 
       setTimeout(function () {
@@ -240,7 +240,7 @@ describe('api', function () {
       if (err) return done(err);
       socketPath = path.resolve(dirPath, 'sock');
       const opts = {
-        resources: ['http://unix:' + socketPath + ':/', 'http://unix:' + socketPath + ':/foo'],
+        resources: ['http://unix:' + socketPath + ':/', 'http://unix:' + socketPath + ':/foo']
       };
 
       setTimeout(function () {
@@ -263,7 +263,7 @@ describe('api', function () {
       if (err) return done(err);
       socketPath = path.resolve(dirPath, 'sock');
       const opts = {
-        resources: ['http-get://unix:' + socketPath + ':/', 'http-get://unix:' + socketPath + ':/foo'],
+        resources: ['http-get://unix:' + socketPath + ':/', 'http-get://unix:' + socketPath + ':/foo']
       };
 
       setTimeout(function () {
@@ -287,7 +287,7 @@ describe('api', function () {
       if (err) return done(err);
       const opts = {
         resources: [path.resolve(dirPath, 'foo')],
-        timeout: 1000,
+        timeout: 1000
       };
       waitOn(opts, function (err) {
         expect(err).toExist();
@@ -301,7 +301,7 @@ describe('api', function () {
       if (err) return done(err);
       const opts = {
         resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
-        timeout: 1000,
+        timeout: 1000
       };
       fs.writeFile(opts.resources[0], 'data', function () {});
       waitOn(opts, function (err) {
@@ -316,7 +316,7 @@ describe('api', function () {
       resources: ['http://localhost:3002'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     setTimeout(function () {
@@ -338,7 +338,7 @@ describe('api', function () {
       resources: ['http://localhost:3010'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     waitOn(opts, function (err) {
@@ -353,7 +353,7 @@ describe('api', function () {
       timeout: 1000,
       interval: 100,
       window: 100,
-      httpTimeout: 70,
+      httpTimeout: 70
     };
 
     httpServer = http.createServer().on('request', function (req, res) {
@@ -376,7 +376,7 @@ describe('api', function () {
       interval: 100,
       window: 100,
       followRedirect: false,
-      resources: ['http://localhost:3000'],
+      resources: ['http://localhost:3000']
     };
 
     httpServer = http.createServer().on('request', function (req, res) {
@@ -399,7 +399,7 @@ describe('api', function () {
       resources: ['http-get://localhost:3010'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     waitOn(opts, function (err) {
@@ -413,7 +413,7 @@ describe('api', function () {
       resources: ['https://localhost:3010/foo/bar'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     waitOn(opts, function (err) {
@@ -427,7 +427,7 @@ describe('api', function () {
       resources: ['https-get://localhost:3010/foo/bar'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     waitOn(opts, function (err) {
@@ -442,7 +442,7 @@ describe('api', function () {
       interval: 100,
       window: 100,
       followRedirect: false,
-      resources: ['http-get://localhost:3000'],
+      resources: ['http-get://localhost:3000']
     };
 
     httpServer = http.createServer().on('request', function (req, res) {
@@ -463,7 +463,7 @@ describe('api', function () {
   it('should timeout when a service is not listening to tcp port', function (done) {
     const opts = {
       resources: ['tcp:localhost:3010'],
-      timeout: 1000,
+      timeout: 1000
     };
 
     waitOn(opts, function (err) {
@@ -481,7 +481,7 @@ describe('api', function () {
         resources: ['socket:' + socketPath],
         timeout: 1000,
         interval: 100,
-        window: 100,
+        window: 100
       };
 
       waitOn(opts, function (err) {
@@ -495,7 +495,7 @@ describe('api', function () {
     const opts = {
       resources: ['tcp:256.0.0.1:1234'],
       timeout: 1000,
-      tcpTimeout: 1000,
+      tcpTimeout: 1000
     };
 
     waitOn(opts, function (err) {
@@ -513,7 +513,7 @@ describe('api', function () {
         resources: ['http://unix:' + socketPath + ':/', 'http://unix:' + socketPath + ':/foo'],
         timeout: 1000,
         interval: 100,
-        window: 100,
+        window: 100
       };
 
       setTimeout(function () {
@@ -540,7 +540,7 @@ describe('api', function () {
         resources: ['package.json', 'http://unix:' + socketPath + ':/', 'http://unix:' + socketPath + ':/foo'],
         timeout: 1000,
         interval: 100,
-        window: 100,
+        window: 100
       };
 
       httpServer = http.createServer().on('request', function (req, res) {
@@ -565,7 +565,7 @@ describe('api', function () {
       timeout: 1000,
       tcpTimeout: 1000,
       reverse: true,
-      window: 100,
+      window: 100
     };
 
     waitOn(opts, function (err) {
@@ -580,7 +580,7 @@ describe('api', function () {
       if (err) return done(err);
       const opts = {
         resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
-        reverse: true,
+        reverse: true
       };
       waitOn(opts, function (err) {
         expect(err).toNotExist();
@@ -594,7 +594,7 @@ describe('api', function () {
       if (err) return done(err);
       const opts = {
         resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
-        reverse: true,
+        reverse: true
       };
       fs.writeFileSync(opts.resources[0], 'data1');
       fs.writeFileSync(opts.resources[1], 'data2');
@@ -615,7 +615,7 @@ describe('api', function () {
       const opts = {
         resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
         reverse: true,
-        timeout: 1000,
+        timeout: 1000
       };
       fs.writeFileSync(opts.resources[0], 'data1');
       fs.writeFileSync(opts.resources[1], 'data2');
@@ -631,7 +631,7 @@ describe('api', function () {
       temp.mkdir({}, function (err, dirPath) {
         if (err) return done(err);
         const opts = {
-          resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
+          resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')]
         };
         fs.writeFileSync(opts.resources[0], 'data1');
         fs.writeFileSync(opts.resources[1], 'data2');
@@ -649,7 +649,7 @@ describe('api', function () {
       temp.mkdir({}, function (err, dirPath) {
         if (err) return done(err);
         const opts = {
-          resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
+          resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')]
         };
 
         setTimeout(function () {
@@ -672,7 +672,7 @@ describe('api', function () {
         if (err) return done(err);
         const opts = {
           resources: [path.resolve(dirPath, 'foo')],
-          timeout: 1000,
+          timeout: 1000
         };
         waitOn(opts)
           .then(function () {
@@ -690,7 +690,7 @@ describe('api', function () {
         if (err) return done(err);
         const opts = {
           resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
-          timeout: 1000,
+          timeout: 1000
         };
         fs.writeFile(opts.resources[0], 'data', function () {});
         waitOn(opts)
@@ -709,7 +709,7 @@ describe('api', function () {
         if (err) return done(err);
         const opts = {
           resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
-          reverse: true,
+          reverse: true
         };
         waitOn(opts)
           .then(function () {
@@ -726,7 +726,7 @@ describe('api', function () {
         if (err) return done(err);
         const opts = {
           resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
-          reverse: true,
+          reverse: true
         };
         fs.writeFileSync(opts.resources[0], 'data1');
         fs.writeFileSync(opts.resources[1], 'data2');
@@ -750,7 +750,7 @@ describe('api', function () {
         const opts = {
           resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
           reverse: true,
-          timeout: 1000,
+          timeout: 1000
         };
         fs.writeFileSync(opts.resources[0], 'data1');
         fs.writeFileSync(opts.resources[1], 'data2');
diff --git a/test/cli.mocha.js b/test/cli.mocha.js
index b327438..e4e9369 100644
--- a/test/cli.mocha.js
+++ b/test/cli.mocha.js
@@ -40,7 +40,7 @@ describe('cli', function () {
     temp.mkdir({}, function (err, dirPath) {
       if (err) return done(err);
       const opts = {
-        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar/deeper/deep/yet')],
+        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar/deeper/deep/yet')]
       };
       fs.writeFileSync(opts.resources[0], 'data1');
       mkdirp.sync(path.dirname(opts.resources[1]));
@@ -57,7 +57,7 @@ describe('cli', function () {
     temp.mkdir({}, function (err, dirPath) {
       if (err) return done(err);
       const opts = {
-        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar/deeper/deep/yet')],
+        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar/deeper/deep/yet')]
       };
 
       setTimeout(function () {
@@ -75,7 +75,7 @@ describe('cli', function () {
 
   it('should succeed when http resources become available later', function (done) {
     const opts = {
-      resources: ['http://localhost:8123', 'http://localhost:8123/foo'],
+      resources: ['http://localhost:8123', 'http://localhost:8123/foo']
     };
 
     setTimeout(function () {
@@ -93,7 +93,7 @@ describe('cli', function () {
 
   it('should succeed when http resources become available later via redirect', function (done) {
     const opts = {
-      resources: ['http://localhost:8123'],
+      resources: ['http://localhost:8123']
     };
 
     setTimeout(function () {
@@ -115,7 +115,7 @@ describe('cli', function () {
 
   it('should succeed when http GET resources become available later', function (done) {
     const opts = {
-      resources: ['http-get://localhost:8124', 'http-get://localhost:8124/foo'],
+      resources: ['http-get://localhost:8124', 'http-get://localhost:8124/foo']
     };
 
     setTimeout(function () {
@@ -133,7 +133,7 @@ describe('cli', function () {
 
   it('should succeed when http GET resources become available later via redirect', function (done) {
     const opts = {
-      resources: ['http-get://localhost:8124'],
+      resources: ['http-get://localhost:8124']
     };
 
     setTimeout(function () {
@@ -171,7 +171,7 @@ describe('cli', function () {
 
   it('should succeed when a service is listening to tcp port', function (done) {
     const opts = {
-      resources: ['tcp:localhost:3030', 'tcp:3030'],
+      resources: ['tcp:localhost:3030', 'tcp:3030']
     };
 
     setTimeout(function () {
@@ -193,7 +193,7 @@ describe('cli', function () {
       if (err) return done(err);
       socketPath = path.resolve(dirPath, 'sock');
       const opts = {
-        resources: ['socket:' + socketPath],
+        resources: ['socket:' + socketPath]
       };
 
       setTimeout(function () {
@@ -214,7 +214,7 @@ describe('cli', function () {
       if (err) return done(err);
       socketPath = path.resolve(dirPath, 'sock');
       const opts = {
-        resources: ['http://unix:' + socketPath + ':/', 'http://unix:' + socketPath + ':/foo'],
+        resources: ['http://unix:' + socketPath + ':/', 'http://unix:' + socketPath + ':/foo']
       };
 
       setTimeout(function () {
@@ -237,7 +237,7 @@ describe('cli', function () {
       if (err) return done(err);
       socketPath = path.resolve(dirPath, 'sock');
       const opts = {
-        resources: ['http-get://unix:' + socketPath + ':/', 'http-get://unix:' + socketPath + ':/foo'],
+        resources: ['http-get://unix:' + socketPath + ':/', 'http-get://unix:' + socketPath + ':/foo']
       };
 
       setTimeout(function () {
@@ -261,7 +261,7 @@ describe('cli', function () {
       if (err) return done(err);
       const opts = {
         resources: [path.resolve(dirPath, 'foo')],
-        timeout: 1000,
+        timeout: 1000
       };
       // timeout is in FAST_OPTS
       execCLI(opts.resources.concat(FAST_OPTS), {}).on('exit', function (code) {
@@ -276,7 +276,7 @@ describe('cli', function () {
       if (err) return done(err);
       const opts = {
         resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
-        timeout: 1000,
+        timeout: 1000
       };
       fs.writeFile(opts.resources[0], 'data', function () {});
       // timeout is in FAST_OPTS
@@ -292,7 +292,7 @@ describe('cli', function () {
       resources: ['http://localhost:3998'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     setTimeout(function () {
@@ -314,7 +314,7 @@ describe('cli', function () {
       resources: ['http://localhost:3999'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     // timeout is in FAST_OPTS
@@ -330,7 +330,7 @@ describe('cli', function () {
       timeout: 1000,
       interval: 100,
       window: 100,
-      httpTimeout: 70,
+      httpTimeout: 70
     };
 
     httpServer = http.createServer().on('request', function (req, res) {
@@ -354,7 +354,7 @@ describe('cli', function () {
       resources: ['http-get://localhost:3999'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     // timeout, interval, window are in FAST_OPTS
@@ -369,7 +369,7 @@ describe('cli', function () {
       resources: ['https://localhost:3010/foo/bar'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     // timeout, interval, window are in FAST_OPTS
@@ -384,7 +384,7 @@ describe('cli', function () {
       resources: ['https-get://localhost:3010/foo/bar'],
       timeout: 1000,
       interval: 100,
-      window: 100,
+      window: 100
     };
 
     // timeout, interval, window are in FAST_OPTS
@@ -397,7 +397,7 @@ describe('cli', function () {
   it('should timeout when a service is not listening to tcp port', function (done) {
     const opts = {
       resources: ['tcp:localhost:3010'],
-      timeout: 1000,
+      timeout: 1000
     };
 
     // timeout is in FAST_OPTS
@@ -411,7 +411,7 @@ describe('cli', function () {
     const opts = {
       resources: ['tcp:256.0.0.1:1234'],
       timeout: 1000,
-      tcpTimeout: 1000,
+      tcpTimeout: 1000
     };
 
     const addOpts = '--tcpTimeout 1000'.split(' ');
@@ -431,7 +431,7 @@ describe('cli', function () {
         resources: ['socket:' + socketPath],
         timeout: 1000,
         interval: 100,
-        window: 100,
+        window: 100
       };
 
       // timeout, interval, window are in FAST_OPTS
@@ -451,7 +451,7 @@ describe('cli', function () {
         resources: ['http://unix:' + socketPath + ':/', 'http://unix:' + socketPath + ':/foo'],
         timeout: 1000,
         interval: 100,
-        window: 100,
+        window: 100
       };
 
       setTimeout(function () {
@@ -474,7 +474,7 @@ describe('cli', function () {
     temp.mkdir({}, function (err, dirPath) {
       if (err) return done(err);
       const opts = {
-        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
+        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')]
       };
       const OPTS = FAST_OPTS.concat(['-r']);
       execCLI(opts.resources.concat(OPTS), {}).on('exit', function (code) {
@@ -488,7 +488,7 @@ describe('cli', function () {
     temp.mkdir({}, function (err, dirPath) {
       if (err) return done(err);
       const opts = {
-        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
+        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')]
       };
       fs.writeFileSync(opts.resources[0], 'data1');
       fs.writeFileSync(opts.resources[1], 'data2');
@@ -508,7 +508,7 @@ describe('cli', function () {
     temp.mkdir({}, function (err, dirPath) {
       if (err) return done(err);
       const opts = {
-        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')],
+        resources: [path.resolve(dirPath, 'foo'), path.resolve(dirPath, 'bar')]
       };
       fs.writeFileSync(opts.resources[0], 'data1');
       fs.writeFileSync(opts.resources[1], 'data2');
@@ -524,7 +524,7 @@ describe('cli', function () {
     const opts = {
       resources: ['tcp:256.0.0.1:1234'],
       timeout: 1000,
-      tcpTimeout: 1000,
+      tcpTimeout: 1000
     };
     // timeout is in FAST_OPTS
     const OPTS = FAST_OPTS.concat(['-r', '--tcpTimeout', '1000']);
@@ -533,4 +533,40 @@ describe('cli', function () {
       done();
     });
   });
+
+  context('resources are specified in config', () => {
+    it('should succeed when http resources become available later', function (done) {
+      setTimeout(function () {
+        httpServer = http.createServer().on('request', function (req, res) {
+          res.end('data');
+        });
+        httpServer.listen(8123, 'localhost');
+      }, 300);
+
+      execCLI(['--config', path.join(__dirname, 'config-http-resources.js')].concat(FAST_OPTS), {}).on(
+        'exit',
+        function (code) {
+          expect(code).toBe(0);
+          done();
+        }
+      );
+    });
+
+    it('should succeed when http resources from command line become available later (ignores config resources)', function (done) {
+      setTimeout(function () {
+        httpServer = http.createServer().on('request', function (req, res) {
+          res.end('data');
+        });
+        httpServer.listen(3030, 'localhost');
+      }, 300);
+
+      execCLI(
+        ['--config', path.join(__dirname, 'config-http-resources.js'), 'http://localhost:3030/'].concat(FAST_OPTS),
+        {}
+      ).on('exit', function (code) {
+        expect(code).toBe(0);
+        done();
+      });
+    });
+  });
 });
diff --git a/test/config-http-resources.js b/test/config-http-resources.js
new file mode 100644
index 0000000..9266535
--- /dev/null
+++ b/test/config-http-resources.js
@@ -0,0 +1,3 @@
+module.exports = {
+  resources: ['http://localhost:8123', 'http://localhost:8123/foo'],
+};