Based on:

http://ultra.ap.krakow.pl/~bar/DOC/ssh_backup.html

How to copy something (that does not need to be a file) to the host:

cat localfile | ssh target_address cat ">" remotefile

cat localfile | gzip -c -1 | ssh target_address cat “>” remotefile.gz

This was used in an ‘adb shell’, to copy /dev/block/mmcblk0 to my host.