If you have to import/export your MARCXML records in Invenio, tind.io offers this great online utility: https://tools.tind.io/xml/xml-manipulation/ that allows to manipulate marcxml.
Exporting marc is not only useful on migration processes, but also when you have to perform changes to a lot of records in your Invenio system. It is way better than performing those changes at database level.
You can export records using web interface or command line. I prefer this second method, using BibExport:
First change this config file: /opt/invenio/etc/bibexport/marcxml.cfg
The MARCXML exporting method export all the records matching a particular search query, zip them and move them to the requested folder. The output of this exporting method is similar to what one would get by listing the records in MARCXML from the web search interface.
Default configurations are given below. The job would have exported all records from the Book collection into one xml.-file and all articles with the author “Polyakov, A M” into another.
[export_job] export_method = marcxml [export_criterias] books = 980__a:BOOK polyakov_articles = 980__a:ARTICLE and author:"Polyakov, A M"
the job is run by this command:
/opt/invenio/bin/bibexport -u admin -wmarcxml
Default folder for storing is: