diff --git a/packages/owl-bot/src/bin/commands/validate.ts b/packages/owl-bot/src/bin/commands/validate.ts
index 412e8b2494c..7366b8a5e32 100644
--- a/packages/owl-bot/src/bin/commands/validate.ts
+++ b/packages/owl-bot/src/bin/commands/validate.ts
@@ -17,31 +17,86 @@
 import {owlBotYamlFromText} from '../../config-files';
 import {promisify} from 'util';
 import {readFile} from 'fs';
+import * as fs from 'fs';
 import yargs = require('yargs');
+import {collectConfigs} from '../../configs-store';
 
 const readFileAsync = promisify(readFile);
 
 interface Args {
   config: string;
+  'ignore-regexp': string[];
 }
 
 export const validate: yargs.CommandModule<{}, Args> = {
-  command: 'validate <config>',
-  describe: 'validate .OwlBot.yaml',
+  command: 'validate <config>|<directory>',
+  describe: 'validates a config or all the configs in a directory',
   builder(yargs) {
-    return yargs.option('config', {
-      describe: 'path to .OwlBot.yaml',
-      type: 'string',
-      demand: true,
-    });
+    return yargs
+      .option('config', {
+        describe: 'path to .OwlBot.yaml or directory',
+        type: 'string',
+        demand: true,
+      })
+      .option('ignore-regexp', {
+        describe:
+          'regular expression of paths to ignore while scanning the ' +
+          'directory.  Example: .*/templates/.*',
+        type: 'array',
+        demand: false,
+        default: [],
+      });
   },
   async handler(argv) {
-    try {
-      const yamlText = await readFileAsync(argv.config, 'utf8');
-      owlBotYamlFromText(yamlText);
-      console.info(`${argv.config} is valid`);
-    } catch (e) {
-      console.info(e);
+    const stat = fs.statSync(argv.config);
+    if (stat.isFile()) {
+      // Validate one config.
+      try {
+        const yamlText = await readFileAsync(argv.config, 'utf8');
+        owlBotYamlFromText(yamlText);
+        console.info(`${argv.config} is valid`);
+      } catch (e) {
+        console.error(e);
+        const error = e instanceof Error ? e : Error(String(e));
+        yargs.exit(-1, error);
+      }
+    } else if (stat.isDirectory()) {
+      // Validate all the configs in the directory.
+      const configs = collectConfigs(argv.config);
+
+      // Tell the user all the valid configs.
+      for (const config of configs.yamls) {
+        console.log(`${config.path} is valid`);
+      }
+
+      // Ignore the bad configs the user asked us to ignore.
+      const ignores = argv['ignore-regexp'].map(pattern => new RegExp(pattern));
+      const badConfigs = configs.badConfigs.filter(
+        config =>
+          !ignores.some(regexp => {
+            const matched = regexp.exec(config.path);
+            if (matched) {
+              console.log('ignored error in', config.path);
+            }
+            return matched;
+          })
+      );
+
+      // Report the bad configs.
+      for (const config of badConfigs) {
+        for (const error of config.errorMessages) {
+          console.error(`${config.path}: ${error}`);
+        }
+      }
+      if (badConfigs.length > 0) {
+        const errorMessage = `${badConfigs.length} invalid config(s).`;
+        console.error(errorMessage);
+        yargs.exit(-1, new Error(errorMessage));
+      }
+    } else {
+      const errorMessage = `${argv.config} isn't a file or a directory.`;
+      console.error(errorMessage);
+      yargs.exit(-2, new Error(errorMessage));
     }
   },
 };