<p>I am looking for a regex that will find repeating letters. So any letter twice or more, for example:</p>

<pre><code>booooooot or abbott
</code></pre>

<p>I won't know the letter I am looking for ahead of time. </p>

<p>This is a question I was asked in interviews and then asked in interviews. Not so many people get it correct.</p>

Use \N to refer to previous groups:
```
```
/(\w)\1+/g
```
```