It would be nice if there were a section of the website dedicated to installation instructions. I just switched to Linux Mint (17.2) and I can't get this .sh file to work and nowhere do I find a step-by-step guide how to do it.

I have already activated "Allow executing file as program" but neither RUN nor RUN IN TERMINAL does anything when I double click the .sh file...

Just drag and drop .sh file into terminal so the path shows up and then hit Enter.

Edit: well, assuming that drag and drop works... ;P

nvm

when I drag+drop and press enter it notifies me I want to open an executable text file. Choosing RUN or RUN IN TERMINAL doesn't do anything, pressing enter again tells me

/bin/sh: 0: Can't open /home/arvid4prez/desktop/BGEE.sh

You might find what you're looking for in this thread by adamhm:
The Big "Try Linux" GOG Game Giveaway

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Oops, I didn't notice you were looking for help installing your games, not your OS.
In that case my ./play.it project might help you:
./play.it, for Debian gamers (and their Ubuntu friends)

I have kind of reproduced the problem by removing permissions to read and write in one of my .sh files, but leaving permission to execute the script. Could you check if your .sh file has permissions to read/write (right click on the .sh -> properties -> Permissions tab)? If not, could you try to change them to at least read and try to run it again?

BTW, when you dragged and dropped file to the terminal, you didn't focus its window which caused executing .sh from Desktop, not the command in the terminal. This caused the pop up/prompt window to show up. ;)

I previously changed the filename to save myself the trouble when typing in the terminal. It didn't work before, either. Changed it back to gog_baldur_s_gate_enhanced_edition_2.0.0.3, no cigar.

Try a sudo chmod +x /path/filename . But normally that should not be necessary.

Why is 'd' in your desktop folder's name written in lowercase?

Would you try copying the file to another folder, say Downloads, setting it as executable and running it from terminal (no drag&drop), then write the output here.

If you run it from terminal, use the following format:
./BGEE.sh
(or whatever is your filename, just notice dot and slash at the beginning) For future reference, you don't need to rename the files. Just start typing the first few letters and press TAB. If there's no ambiguity it will complete the filename for you.

In a Terminal go to the directory where the .sh file is stored.

Type "sudo chmod a+x yourfile.sh" (Don't use quotes, and replace "yourfile.sh" with the name of the .sh file downloaded from GOG).

Then type ./yourfile.sh (once again replacing yourfile).

The game should run. If it doesn't, post what it says in Terminal here :)

I'd guess it will say "No such file or directory" since default terminal directory would be home and commands are not something new users are used to. ;)

But drag and drop into terminal pastes the whole path, which should be easier to deal with at the moment than changing pwd to wherever the file is.

No argue there, but during troubleshooting one should always keep it as transparent as possible and do everything by hand if possible. This ensures isolating the problem more easily without introducing potential errors or mistakes from various sources (which I know sounds like an overkill in this case).

I've tried with 2 games, same result:

~/Desktop $ sudo chmod a+x gog_baldur_s_gate_enhanced_edition_2.0.0.3.sh
~/Desktop $ ./gog_baldur_s_gate_enhanced_edition_2.0.0.3.sh
/bin/sh: 0: Can't open ./gog_baldur_s_gate_enhanced_edition_2.0.0.3.sh

and

~/Desktop $ sudo chmod a+x gog_brutal_legend_2.0.0.2.sh
~/Desktop $ ./gog_brutal_legend_2.0.0.2.sh
/bin/sh: 0: Can't open ./gog_brutal_legend_2.0.0.2.sh

dragging, same thing:

~/Desktop $ '/home/arvid4prez/Desktop/gog_brutal_legend_2.0.0.2.sh' /bin/sh: 0: Can't open /home/arvid4prez/Desktop/gog_brutal_legend_2.0.0.2.sh


Both files have full Read+Write permissions, I am the only user and administrator.