Changing xml-file using Ant

How to change existing xml-file using Ant. For example:开发者_如何学C

<test attr="0">
    ...    
</test>

to

<test attr="1">
...
</test>

---

Use xmltask see <attr> section in particular), eg:

<attr path="//test[@attr='0']/" attr="attr" value="1"/>