Overview
shellinabox is a web based terminal that uses Ajax technology to provide the look and feel of a native shell. It is available in the Ubuntu repositories for Quantal (12.10) and later.
Installation and Setup
Simply install the shellinabox package.
sudo apt-get install shellinabox
The default location for the config file is located /etc/default/shellinabox. This may be edited to change the default port [Default=4200] and other parameters. Also of interest is the directory /etc/shellinabox.
Remember to open up port 4200 if you are running a firewall, and that is it set up on your local machine. You can access it with http://localhost:4200/.
Alternatively, you can download and install one of the Debian packages from the official project page. When you click the download link, your browser should ask if you want to open the .deb file with GDebi Package installer; choose Okay and then click the Install button.
Navigate to https://yourcomputername:4200
Tips
Change the default port
Edit /etc/default/shellinabox so that the default port is 443.
sudo gedit /etc/default/shellinabox
Then restart the shellinabox daemon:
sudo invoke-rc.d shellinabox restart
Now you can access your shellinabox server with an easier URL: https://yourcomputername
Access your shellinbox server from outside your LAN
Configure your home router to forward TCP traffic port 443 (assuming you followed the above tip) to your computer's IP address. You can right click on the Network Manager applet and choose connection information to find your computers IP address. Now you can access your computer when away from home by navigating to https://yourpublicIPaddress. You can get your public IP address by going to http://whatismyip.com. To make it easier to remember your public IP address you can register with a Dynamic DNS service.