Regex for a file name without an extension

Question

I'm looking for a regex expression that will capture a file name that does not have an extension and give me that name in a backreference so I can add an extension. So if someone puts in xyz I can replace it with xyz.html. xyz.php or xyz.html should not be captured. Thanks

Accepted Answer

Use following regular expression:

```
^([^.]+)$
```

meaning filename that only consist of non-dot characters.

UPDATE

added paren for capturing group.

Regex for a file name without an extension

Solution

Problem