2016-07-21 EDIT: add screenshot of web ui

A quick tutorial on getting Syncthing up and running on Ubuntu Touch, without needing r/w on system.

  1. Access the terminal on the device, using either SSH, the terminal app, or adb shell.

  2. Download and extract the tarball for arm64 (or another arch, depending on your device - I set it up on the M10 which is 64bit). The following sequence of commands will be pretty much what needs doing:

    # I like a separate dir for storing downloaded programs
    mkdir apps
    
    # download (note: you could download through the browser - same result)
    cd Downloads
    VERSION="0.13.10" # set this to the version you want to install
    wget https://github.com/syncthing/syncthing/releases/download/v${VERSION}/syncthing-linux-arm64-v${VERSION}.tar.gz
    
    # extract to the apps dir
    tar xzf syncthing-linux-arm64-v${VERSION}.tar.gz -C ~/apps/
    
    # rename for neatness
    cd ~/apps
    mv syncthing-linux-arm64-v${VERSION} syncthing
    
    # now, the tarball is still in ~/Downloads,
    # and the syncthing files are in ~/apps/syncthing
    
  3. Now you can run syncthing by executing ~/apps/syncthing/syncthing. (You can symlink it to somewhere on your path for easier access if you want.) You’ll probably want it to start automatically though - in that case create ~/.config/upstart/syncthing.conf with the following contents (ref. this askubuntu answer):

    description "run syncthing on startup"
    author "Your Name"
    
    start on started unity8-dash
    respawn
    exec /home/phablet/apps/syncthing/syncthing
    
  4. It should now start automatically when you login to your device. You can now check the status of the upstart service with $ status syncthing, and control Syncthing through it’s web ui at http://localhost:8384.

screenshot of syncthing web ui in the ubuntu touch browser Syncthing web ui running locally on the tablet

Beware that since this is a service that is running constantly and performing a lot of disk operations and using the network, it could chew through the battery quicker than expected…