Ok @plissken
Here is what I have for you now... and Wow that seemed a bit harder than I thought ...
So this is for an individual I used _export and _import ... I have not tried _bulk yet
So first I list to find the Object I am after in my initial / default space
# Get Dashboards
curl -X GET -H 'Content-Type: application/json' -H 'kbn-xsrf: true' http://localhost:5601/api/saved_objects/_find?type=dashboard | jq
In this case is is the eCommerce Dashboard
{
"type": "dashboard",
"id": "722b74f0-b882-11e8-a6d9-e546fe2bba5f",
So now I _export it ... it takes both the type and id as far as I can tell in the objects array
# Export the actual Dashboard
curl -X POST -H 'Content-Type: application/json' -H 'kbn-xsrf: true' http://localhost:5601/api/saved_objects/_export -d '{"objects":[{"type":"dashboard","id":"722b74f0-b882-11e8-a6d9-e546fe2bba5f"}]}' > saved-dashboard.ndjson
Now _import to another space look at the syntax careful
# Import to a new space
curl -X POST -H 'kbn-xsrf: true' http://localhost:5601/s/test/api/saved_objects/_import?createNewCopies=true --form file=@saved-dashboard.ndjson
{"successCount":1,"success":true,"warnings":[],"successResults":[{"type":"dashboard","id":"722b74f0-b882-11e8-a6d9-e546fe2bba5f","meta":{"title":"[eCommerce] Revenue Dashboard","icon":"dashboardApp"},"destinationId":"e410188d-e9fd-40cc-bdc9-aa307d0a7165"}]}
And my Pretty new dashboard in my space test
I can probably look at the _bulk at some point if you still need that