How do I POST XML data with curl

-H "text/xml" isn't a valid header. You need to provide the full header:

-H "Content-Type: text/xml" 

It is simpler to use a file (req.xml in my case) with content you want to send -- like this:

curl -H "Content-Type: text/xml" -d @req.xml -X POST http://localhost/asdf

You should consider using type 'application/xml', too (differences explained here)

Alternatively, without needing making curl actually read the file, you can use cat to spit the file into the stdout and make curl to read from stdout like this:

cat req.xml | curl -H "Content-Type: text/xml" -d @- -X POST http://localhost/asdf

Both examples should produce identical service output.

I prefer the following command-line options:

cat req.xml | curl -X POST -H 'Content-type: text/xml' -d @- http://www.example.com

or

curl -X POST -H 'Content-type: text/xml' -d @req.xml http://www.example.com

or

curl -X POST -H 'Content-type: text/xml'  -d '<XML>data</XML>' http://www.example.com