So, for the sake of sharing i will post my instructions original from the itch.io page of Mainlining.

Please note that i did not tested anything on linux but i don't think it should be much of any problems since i only used tools available on both platforms.

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What i did is use innoextract to get the gamefiles from GOG's installer and wine to run the game. Both tools can be installed easily with Homebrew. Enter the following commands from terminal to do so:

brew update
brew install innoextract
brew install wine

After that is installed you can use the following command to extract the installer (Please note that the actual installer's filename could be different):

innoextract setup_mainlining_1.0.02_\(9587\).exe

Cd into the extracted folder and then the 'app' folder where the game files are located in and enter:

wine MainliningGame.exe

Have fun ;)

Above steps (except for the Brew part) probably also work on a linux machine. Tools like Wineskin or the likes may make things easier but above steps feels natural to me since i'm a terminal fan/nerdboy.

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Unfortunately this does not work on Linux, at least not with wine 4.0rc2. Which wine version were you using?