When connecting Android 3.0+ devices to Ubuntu 13.04 file transfers usually work fine in Nautilus but using the command line is not at all obvious. No filesystem mount point is apparent and Nautilus displays the "location" (usually the mount point) as something like
mtp://[usb:002,003]/ if it displays at all. You can also see the location by executing
gvfs-mount -l. Under the covers, Ubuntu uses gvfs for mounting the mtp filesystem that Android exposes. A gvfs mounted mtp share should be accessible from
/run/user/<username>/mtp:host=<encoded string>. However, a gvfs bug in 13.04 (and likely earlier versions) will display indecipherable numbers instead of file objects at that location. A newer version of gvfs fixes this problem. Execute
sudo add-apt-repository ppa:langdalepl/gvfs-mtp sudo apt-get update sudo apt-get dist-upgrade
In Nautilus unmount and remount your mtp share. The listing under
/run/user/<username>/ should now list with proper filenames.
Hat tip to bessman for Where are MTP mounted devices located in the filesystem?. I filled in some steps that beginners may not know about.