<p>Please could someone help me with writing a regex expression to replace 0044 token which will be at the start of the string with a 0. Please note that I do not want to replace all 0044 tokens with 0, only those that appear at the start of the string.</p>

<p>Thanks a lot</p>

In perl:
```
```
s/^0044/0/;
```
```
The
```
^
```
means that the match will only happen at the beginning of the string.