how to? xmlstarlet to extract HTML data by id

The html data has a default namespace that you have to declare in the xmlstarlet command:

xmlstarlet sel \    -N n="http://www.w3.org/1999/xhtml" \    -t \    -c "/n:html/n:body/n:table[@id='test_table']/descendant::*/text()" \htmlfile 2>/dev/null

Once located the <table> element I use descendant::*/text() to extract all text elements of it, and also use 2>/dev/null to skip the warning:

Attempt to load network entity http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd

It yields:

testtestmo test

UPDATE: I didn't know it but as the error message says, there is no need to declare the namespace when it's the default one, so also this works:

xmlstarlet sel \    -t \    -c "/_:html/_:body/_:table[@id='test_table']/descendant::*/text()" \htmlfile 2>/dev/null

As is mentioned in

http://xmlstar.sourceforge.net/doc/UG/ch05.html

common problems when using the

-N x="http://www.w3.org/1999/xhtml" \

option you also have to prefix the node selections with

x:

e.g.

 xmlstarlet sel \  -N x="http://www.w3.org/1999/xhtml" \  -t \  -m "//x:pre" \  -v . somehtml.html

will select all pre nodes

You can try

xmlstarlet ed --inplace -u "html/body/table[@id='your_tabl e_id']/tr[@id='row_id']/td[@id='data_id']" -v NEW_VALUE_TO_BE_CHANGED HTMLFILE_NAME 2>/dev/null