diff --git a/src/util.js b/src/util.js
index 86a5dc12..febe4125 100644
--- a/src/util.js
+++ b/src/util.js
@@ -212,6 +212,14 @@ async function e_call(argv, script, ...args) {
     return;
   }
 
+  if (argv.verbose !== undefined &&
+    // this must exclude NaN -- yargs default value for numeric type
+    !(argv.verbose >= 0 && argv.verbose <= 5)) {
+    console.warn("invalid value for --verbose option: must be a number between 0 and 5");
+    process.exit(1);
+    return;
+  }
+
   return new Promise(resolve => {
     let _path = el_script(script);
 
diff --git a/test/jest/options.test.js b/test/jest/options.test.js
index bcc97e0b..42aa4323 100644
--- a/test/jest/options.test.js
+++ b/test/jest/options.test.js
@@ -18,6 +18,18 @@ describe("options", () => {
     });
   });
 
+  describe("verbose option", () => {
+    it("should error if no number is given", async () => {
+      await expect(ctx.runEask("info -v")).rejects.toMatchObject({ code: 1 });
+    });
+
+    it("should error if the number is omitted before the next option", async () => {
+      await expect(ctx.runEask("info -v --no-color")).rejects.toMatchObject({
+        code: 1,
+      });
+    });
+  });
+
   test.each([
     "-a",
     "--all",