Remove nodes in xml based on sub-node value

Question

I'm working with a wordpress xml dump, and for whatever reason, wordpress has exported every user in our database as an "author" of each post. In order to make the xml file easier to work with, I would like to remove all of the author nodes except for one.

Here's an example of what I have:

    <rss version="2.0" xmlns:excerpt="http://wordpress.org/export/1.2/excerpt/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:wp="http://wordpress.org/export/1.2/">
<wp:author>
    <wp:author_id>35622</wp:author_id>
    <wp:author_login>some_username_1</wp:author_login>
    <wp:author_email>[email protected]</wp:author_email>
    <wp:author_display_name><![CDATA[some_username_1]]></wp:author_display_name>
    <wp:author_first_name><![CDATA[]]></wp:author_first_name>
    <wp:author_last_name><![CDATA[]]></wp:author_last_name>
</wp:author>
<wp:author>
    <wp:author_id>35290</wp:author_id>
    <wp:author_login>my_unique_username</wp:author_login>
    <wp:author_email>[email protected]</wp:author_email>
    <wp:author_display_name><![CDATA[my_unique_username]]></wp:author_display_name>
    <wp:author_first_name><![CDATA[]]></wp:author_first_name>
    <wp:author_last_name><![CDATA[]]></wp:author_last_name>
</wp:author>
<wp:author>
    <wp:author_id>35289</wp:author_id>
    <wp:author_login>some_username_2</wp:author_login>
    <wp:author_email>[email protected]</wp:author_email>
    <wp:author_display_name><![CDATA[some_username_2]]></wp:author_display_name>
    <wp:author_first_name><![CDATA[]]></wp:author_first_name>
    <wp:author_last_name><![CDATA[]]></wp:author_last_name>
</wp:author>
<wp:author>
    <wp:author_id>33404</wp:author_id>
    <wp:author_login>some_username_3</wp:author_login>
    <wp:author_email>[email protected]</wp:author_email>
    <wp:author_display_name><![CDATA[some_username_3]]></wp:author_display_name>
    <wp:author_first_name><![CDATA[]]></wp:author_first_name>
    <wp:author_last_name><![CDATA[]]></wp:author_last_name>
</wp:author>

Times a few thousand more entries

I would like to remove all of the nodes except for this one:

<wp:author>
    <wp:author_id>35290</wp:author_id>
    <wp:author_login>my_unique_username</wp:author_login>
    <wp:author_email>[email protected]</wp:author_email>
    <wp:author_display_name><![CDATA[my_unique_username]]></wp:author_display_name>
    <wp:author_first_name><![CDATA[]]></wp:author_first_name>
    <wp:author_last_name><![CDATA[]]></wp:author_last_name>
</wp:author>

Attempting to do this in a shell script but I'm not really sure where to start as I've never used xmlstarlet before so would appreciate any help.

Updated to reflect data root and solution that I found:

xmlstarlet ed -d "//wp:author[wp:author_id != '35290']" file.xml > out.xml

Keldek · Accepted Answer · 2019-02-22 21:19:55Z

1

The solution I found is as follows:

xmlstarlet ed -d "//wp:author[wp:author_id != '35290']" file.xml > out.xml

answered Feb 22, 2019 at 21:19

Keldek

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Comments

glenn jackman · Accepted Answer · 2019-02-22 00:54:42Z

0

Taking just a snippet out of an XML file doesn't really give us enough to provide a complete answer. I wrapped this sample data in a root tag:

<root xmlns:wp="some.url">
...
</root

Then you can provide an XPath expression to find the node you're looking for: all "wp:author" nodes that contain a "wp:author_id" child with the specific value.

$ xmlstarlet sel -t -c '//wp:author[wp:author_id = "35289"]' file.xml
<wp:author xmlns:wp="some.url">
    <wp:author_id>35289</wp:author_id>
    <wp:author_login>some_username_2</wp:author_login>
    <wp:author_email>[email protected]</wp:author_email>
    <wp:author_display_name>some_username_2</wp:author_display_name>
    <wp:author_first_name></wp:author_first_name>
    <wp:author_last_name></wp:author_last_name>
</wp:author>

I've found this page of XPath examples helpful

answered Feb 22, 2019 at 0:54

glenn jackman

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3 Comments

Keldek Over a year ago

My apologies, I'm only adept enough at xml to work with it in php. The correct data root is:

<rss version="2.0" xmlns:excerpt="http://wordpress.org/export/1.2/excerpt/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:wp="http://wordpress.org/export/1.2/">

Keldek Over a year ago

I did eventually find what I was looking for, which is very similar to the example you gave: xmlstarlet ed -d "/rss/channel/wp:author[wp:author_id != '35289']" file.xml > file2.xml

glenn jackman Over a year ago

Good one: that will keep all the enclosing XML tags which my answer does not. I recommend you provide an answer to your own question and then accept it. That will guide future readers to the correct solution.

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