How to insert a new element under another with xmlstarlet?

Question

$ vim test.xml

<?xml version="1.0" encoding="UTF-8" ?>
<config>
</config>
$ xmlstarlet ed -i "/config" -t elem -n "sub" -v "" test.xml
<?xml version="1.0" encoding="UTF-8"?>
<sub></sub>
<config>
</config>

But I wanted sub to be a child of config. How should I change the xpath parameter of -i?

BONUS: Is it possible to insert the child directly with an attribute and even have it set to a value? Something like:

$ xmlstarlet ed -i "/config" -t elem -n "sub" -v ""  -a attr -n "class" -v "com.foo" test.xml

Answer 1

Use -s (or --subnode) instead of -i. Regarding the bonus, you can't insert an element with an attribute directly but since every edit operation is performed in sequence, to insert an element and then add an attribute:

> xml ed -s /config -t elem -n sub -v "" -i /config/sub -t attr -n class -v com.foo test.xml
<?xml version="1.0" encoding="UTF-8"?>
<config>
<sub class="com.foo"></sub></config>