Stolen from linoxide.com

Step 1) Installing Dropbox from Command Line

We will install the wget package using the apt command.

    $ sudo apt-get update
      $ sudo apt-get install wget
    

Dropbox cli version is available for both 32 and 64 bit editions, we will download Dropbox upon out version.

    32-bit
      $ cd ~ && wget -O - "https://www.dropbox.com/download?plat=lnx.x86" | tar xzf -
    

    64-bit
      $ cd ~ && wget -O - "https://www.dropbox.com/download?plat=lnx.x86_64" | tar xzf -
    

After executing this command, It will create a new hidden folder named .dropbox-dist in our $HOME directory.

Run the following command to start the Dropbox from .dropbox-dist folder.

$ ~/.dropbox-dist/dropboxd

    Output
      This computer isn't linked to any Dropbox account...
      Please visit https://www.dropbox.com/cli_link_nonce?nonce=35ff549233f01a5d4e699826b0ab6ffb to link this device.
    

Now open the browser and navigate to the above link to connect system with your dropbox account.

Enter Dropbox username, password and click Sign-in.

The server is connected to our dropbox account, we should see a message like below.

This computer is now linked to Dropbox. Welcome Smart

Folder named Dropbox will be created in our home directory. keep the data in this folder to access it from any devices.

$ ls Dropbox/

    Output
      'Get Started with Dropbox.pdf'
      python3_tutorial.pdf
      Screenshots
      'Simply Raspberry Pi.pdf'
      smart.zip
    

Congratulations! The Ubuntu server has been linked to our dropbox account. The dropbox will keep running until we stop it by pressing CTRL + C. We should start it manually every time
when we want to use dropbox.

Step 2) Installing Dropbox CLI

Frist thing we will install Python using command below.

sudo apt install python

Now, Download the dropbox python script and put it in our PATH, for example /usr/local/bin/.

$ sudo wget -O /usr/local/bin/dropbox "https://www.dropbox.com/download?dl=packages/dropbox.py"

Make it executable:

$ sudo chmod +x /usr/local/bin/dropbox

Now we can start using the dropbox cli. To display help, simply run:

$ dropbox

    Output
      Dropbox command-line interface
      
      commands:
      
      Note: use dropbox help <command> to view usage for a specific command.
      
      status       get current status of the dropboxd
      throttle     set bandwidth limits for Dropbox
      help         provide help
      stop         stop dropboxd
      running      return whether dropbox is running
      start        start dropboxd
      filestatus   get current sync status of one or more files
      ls           list directory contents with current sync status
      autostart    automatically start dropbox at login
      exclude      ignores/excludes a directory from syncing
      lansync      enables or disables LAN sync
      sharelink    get a shared link for a file in your dropbox
      proxy        set proxy settings for Dropbox
    

To view the usage of a specific command, for example running, run:

$ dropbox help running

    output
      dropbox running
      
      Returns 1 if running 0 if not running.
    

To see if dropbox service is running or not. Type command below.

$ dropbox status

    Output
      Dropbox isn't running!
    

To start dropbox service. Type command below.

$ dropbox start

Let us again check if it is running using command.

$ dropbox status

    Output
      Up to date
    

It will keep running until we reboot the system.

To stop dropbox service. Type command below.

$ dropbox stop

    output
      Dropbox daemon stopped.
    

To get the current sync status of a file, Type command below.

$ dropbox filestatus Dropbox/smart.txt

    Output
      Dropbox/smart.txt: up to date
    

we can exclude a directory from syncing. For instance, We will exclude dir1 folder using command below.

$ dropbox exclude add dir1

We can add multiple directories with space separated values to exclude them from syncing like below.

$ dropbox exclude add dir1 dir2

To view the list of directories currently excluded from syncing, Type command below.

$ dropbox exclude list

To remove a directory from the exclusion list, Type command below.

$ dropbox exclude remove dir2

To get a shared link for a file, for example smart.txt, in our dropbox folder, Type command below.

$ dropbox sharelink Dropbox/smart.txt

    Output
      https://www.dropbox.com/s/rqteaol58c1zlkw/smart.txt?dl=0
    

We can now pass the above URL to anyone.

To enable lansync, Type command below.

$ dropbox lansync y

To disable lansync, Type command below.

$ dropbox lansync n

Step 3) Starting Dropbox Automatically Every Reboot

We can make Dropbox service to automatically start on every reboot. Create a systemd service unit for Dropbox.

$ sudo nano /etc/systemd/system/dropbox.service

Add the following lines:

[Unit]
      Description=Dropbox Service
      After=network.target
      
      [Service]
      ExecStart=/bin/sh -c '/usr/local/bin/dropbox start'
      ExecStop=/bin/sh -c '/usr/local/bin/dropbox stop'
      PIDFile=${HOME}/.dropbox/dropbox.pid
      User=smart
      Group=smart
      Type=forking
      Restart=on-failure
      RestartSec=5
      StartLimitInterval=60s
      StartLimitBurst=3
      
      [Install]
      WantedBy=multi-user.target
    

Replace User, Group and dropbox cli path /usr/local/bin/ with our own values. Save and quite the file.

Reload daemon using command below.

$ sudo systemctl daemon-reload

Enable dropbox service using command below.

$ sudo systemctl enable dropbox

Start dropbox service using command below.

$ sudo systemctl start dropbox

Now dropbox service will automatically start at every reboot.

Check running of the service using command below.

$ sudo systemctl status dropbox