Mount /sdcard with Linux
If you want to give adbfs a try, here are some instructions. You need to take care to grab the right one, as there are two projects around: one is simply called adbfs, I couldn't get that to work correctly. The other is adbfs-rootless:


go to the projects github page
on that page, at the right-hand side in about the middle of the page, you find a button labeled Download ZIP. Click that to download the sources.
create a new directory, e.g. mkdir ~/adbfs-rootless, and extract the .zip to it
now first install the dependencies: sudo apt-get install libfuse-dev
change to the directory (cd ~/adbfs-rootless), and build the binaries by simply running make
copy the resulting adbfs binary into your $PATH, where your adb binary is located (for ADB, see Is there a minimal installation of ADB?)


Now you're ready to go. Another one-time job is to create a mountpoint, e.g. mkdir ~/droid. After that, connect your Android device via ADB (after having enabled USB debugging, of course). Then mount it using adb ~/droid, and do whatever you wanted to do (e.g. running rsync, copying stuff, whatever). When you're done, don't forget to disconnect: fusermount -u ~/droid.

To make things easier, I created two aliases:

alias mdroid="adb ~/droid"
alias udroid="fusermount -u ~/droid"


So I only need to type mdroid to mount, and udroid to unmount the device.

Enjoy the fun!