I would like to know if it is possible to choose where a .deb file will be installed, or if it is possible to move it after the installation to another directory without troubles for the app.
I am asking that because I am running Ubuntu on a 32Go's SSD, and I would like to install some games from Humble Bundle on my other HDD.
There is a similar Q&A at superuser.com dealing with that question. A more specific question was asked also here at askubuntu.com.
Your choices are:
Use symlinks. Open the *.deb package with the archive manager. This tells you where the files go. Move those directories to your external harddisc and put a symlink at the origin. Be careful to move only directories from your games and not shared libraries or so!
Mount your external hardrive or some of its folders (a second time) at the game's path. E.g. /usr/share/games might be good candidate for your external harddisc. You can use the bind option, e.g.:
sudo mount --bind /media/external-hardisc/usr-share-games /usr/share/games
Don't use a *.deb package, but install directly from source to a directory of your choice.
Use the dpkg parameter --root to change the install location. The man page says:
--root=dir
Changing root changes instdir to dir and admindir to
dir/var/lib/dpkg.
There is no guarantee that this will work. The program might not be able to deal with the different location.
(This list of solutions is not exhaustive.)
