Mount Google Drive and Dropbox to system (only online)
The current answer is incorrect. There is actually a way to mount your cloud storage as if it were its own drive.
The method is called google-drive-ocamlfuse. There is a version for 16.04 and down to at least 12.10.
To install it, you do need to add the PPA, but I've used it before and trust it.
sudo add-apt-repository ppa:alessandro-strada/ppa
sudo apt-get update
sudo apt-get install google-drive-ocamlfuse
Usage instructions from WEB UPD8:
Run google-drive-ocamlfuse to authorize it with your account.
Make a directory somewhere (~/gdrive for example): mkdir ~/gdrive.
Mount Google Drive to the folder you created: google-drive-ocamlfuse ~/gdrive
By default, the app only refreshes lists every 60 seconds. You can change this in the config file: ~/.gdfuse/default/config.
To make it mount on startup, add this command to Startup Applications (Unity): google-drive-ocamlfuse /path/to/gdrive. Even if you made the folder in your user directory, use an absolute path for this.
As for Dropbox, something a little more general exists: CloudFusion. This actually supports both Google Drive and Dropbox, but it looks like it only works for one at a time.
The installation is a bit more manual for this one.
sudo apt-get install git
git clone git://github.com/joe42/CloudFusion.git
sudo apt-get install python-setuptools gcc libssl-dev libffi-dev python-dev fuse-utils opencv-dev libhighgui2.4 libcvaux2.4 sikuli-ide python-pycurl python-libxml2 python-imaging tesseract-ocr
cd CloudFusion
sudo python setup.py install
The GitHub page has full configuration instructions.
For Dropbox:
Simply copy the Dropbox configuration file located at cloudfusion/cloudfusion/config/Dropbox.ini to your home directory. If you do not have a Dropbox account already, you can create a new one at https://www.dropbox.com. Edit the configuration file by adding your username and a password.
For Google Drive:
Copy the Google Drive configuration file located at cloudfusion/cloudfusion/config/GDrive.ini to your home directory. Add your client_id, and client_secret to the configuration file. Details on obtaining these are inside the configuration file.
To start:
cloudfusion --config ~/db.ini mntThis assumes that you saved the configuration file as db.ini to your home directory. If you simply copied the configuration file as suggested, replace db.ini with the respective file; i.e. Sugarsync.ini or Dropbox.ini. If the login process is not yet fully automatized, as with Google Drive, a browser will open, and you have to allow CloudFusion access to your account manually.
Enjoy accessing your files in the directory mnt/data.
For more advanced options, check the linked page.
So, yes it is possible to mount cloud storage, using those two programs.
No, there isn't.
Dropbox has an official sync client for Linux and Google Drive has also an unofficial one, so both can be easily used in a Linux system. However, sync always means copying the contents to the synced local folders, hence using at least as much space.