Again: the basic 'apt-offline' package does not depend on anything that is
not already installed on the default system. One it is installed, you will be
able to easily install any additional package (in particular, 'apt-offline'
will take care of dependency resolution)... including apt-offline-gui if you
wish!
Let me try, again, to explain the steps as clearly as possible:
You must grab the sole "apt-offline" package from the online system you are
using right now (be it Trisquel or not). You need the version of the package
that corresponds to your version of Trisquel:
Click on this link if your offline system is Trisquel 4.0 Taranis
Click on this link if your offline system is Trisquel 5.0 Dagda
Click on this link if your offline system is Trisquel 5.5 Brigantia
Click on this link if your offline system is Trisquel 6.0 Toutatis
The page you have just opened list mirrors that, by definition, host the
exact same file (the package "apt-offline" you want). Choose any of them and
click on it.
Save the file you are downloading onto a removable device (e.g., a USB disk).
Plug this device into the offline Trisquel.
Double-click on the "apt-offline" package.
GDebi, a package installer, should pop up and, after a preliminary warning,
you can click on button to install the package.
Open a terminal (e.g., using Ctrl+Alt+T).
Use the 'apt-offline' to ask for a full upgrade of your system + the
installation of "apt-offline-gui":
$ sudo apt-offline set --update --upgrade --install-package apt-offline-gui
-- /path/to/removable/device/apt.sig
If you do not know the path to the removable device, just write "~/apt.sig"
after " -- " (do not forget the spaces by the way). That will create the
required file in your home directory. You can then move it to the removable
device.
On an online system, install "apt-offline". The exact procedure depends on
the system. If it is Debian-based, you can use Synaptic or, alternatively,
you can run this command in a terminal:
$ sudo apt-get install apt-offline
On Windows, it is harder but possible.
In a terminal, ask 'apt-offline' to download the packages to fulfil the
upgrade/installation demands you expressed on the offline system (you need
not remember them):
$ apt-offline get -d /path/to/removable/device/download-directory
/path/to/removable/device/apt.sig
Back to the offline Trisquel, plug the removable device.
Open a terminal (e.g., using Ctrl+Alt+T).
Fulfil your demands (again, you need not remember them):
$ sudo apt-offline install /path/to/removable/device/download-directory
Explained in details, that looks tedious. It actually is easy. If you install
'apt-offline-gui' (like I suggested along the process), you can then use the
GUI if you prefer.
