How can I access multiple user spaces from adb?

I am running KitKat on a tablet with two users: primary (owner) and secondary. I need to access a file generated by an app of the secondary user. When I plug the tablet into my (Ubuntu) desktop via USB, it mounts as a media device (MTP), and shows me the base folder for the currently active user. But the file I want is elsewhere on the system, so I connected from the command line via adb shell instead. Connecting via ADB gives me access to deeper folders (/mnt /proc etc) but I couldn't find the file where I expected it , so I looked in /sdcard anyway. To my surprise I recognised the contents as the base folder of the owner account, even though the currently active user is the secondary user. This also tells me that, if I ever need to, I won't be able to access the base folder for the secondary user via adb shell. How can I access the tablet from adb shell as the secondary user, rather than the primary (owner) user? (Being able to access the secondary user's files is good enough.) I'm not sure what the proper term here is. I mean the folder with Android, Download and Pictures, specific to a particular user. FWIW I am exporting an OPML file from Flym. Flym reports that the OPML export is generated at /storage/emulated/10/Flym_123456789.opml but I can only get as far as /storage/emulated - there is no subfolder called 10, only legacy which is the same as /sdcard (the primary/owner's base folder, not the secondary user's base folder).