get value in an XML file with xmlStarlet tool

Question

My XML file structure

<properties>
    <structure name="preference">
        <structure name="cam">
            <property name="number" value="8"/>
            <property name="name" value="eddi"/>
        </structure>
    </structure>
</properties>

With XMLstarlet tool, I'm trying to get the value "8" so I first tried this following command:

xmlstarlet -t -v '/properties/structure[@name="preference"]/structure[@name="cam"][property/@name="number"]/@value' file.xml

Then I get these errors:

parser error : attributes construct error
xsl:value-of select="/properties/structure[@name="preference"]

parser error : Couldn't find end of Start Tag value-of line 23
xsl:value-of select="/properties/structure[@name="preference"]

these errors are pointing to "preference".
I saw some topics dealing with this kind of action but their solution doesn't match with my case.

Do you have any idea on how to get this value?

Answer 1

For the updated (by @har07) and valid xml, e.g.:

<properties>
    <structure name="preference">
        <structure name="cam">
            <property name="number" value="8"/>
            <property name="name" value="eddi"/>
        </structure>
    </structure>
</properties>

(Note the self closing tags />)

you could use:

xmlstarlet sel -T -t -m '//property[@name="number"]/@value' -v . -n file.xml

and prints

8

using:

xmlstarlet --version
1.6.1
compiled against libxml2 2.9.4, linked with 20904
compiled against libxslt 1.1.29, linked with 10129