[FEATURE] Option to run program/installer in a game's prefix.

It would be incredibly useful if protontricks could be used to execute a program or installer in a game's wine prefix.

This could be used to run an installer in the game's prefix, run a command, or most importantly regedit.

Set your launch options to PROTON_DUMP_DEBUG_COMMANDS=1 %command%. Then start the game. You will have a script at /tmp/proton_$USER/run that does that.

Yes, I know that exists, but I'm talking about a function that can be integrated into the steam for Linux GUI interface?

Should this feature be moved to the Steam For Linux bug tracker instead, even though it would require changes to both?

Another function for Steam For Linux that would utilize this function would be the ability to launch certain utilities under the games environment from the game preferences dialog. (For instance Wine Settings, controller configuration and Registry Editor.)

Maybe it could be moved there? Steam could have a tab under the properties window for that certain game. There, one could run any programs/installers they need or whatnot (preferably under the name of an "advanced" tab)

This may not be entirely relevant to this issue, but you can start a new shell with winetricks' shell verb (seems to be an undocumented debugging feature?) and do whatever you want there. It doesn't set the Wine environment exactly like how Proton does in @ryao's solution above, but it could be good enough for simple commands.

For example:

$ protontricks 21090 shell
$ # New shell is created with game's Wine prefix env vars. Now, let's run winecfg.
$ winecfg
$ # Or maybe install a fan-made patch?
$ wine fanmade_game_patch.exe

Also, regedit can also be run directly like this, since winetricks already has a verb for it:

$ protontricks 21090 regedit

As for running arbitrary commands prior to/instead of starting the game (eg. possibly using syntax like this in Steam launch settings: protontricks 21090 run 'wine sync_game_mods.exe'; %command%), I haven't found out how to do that easily.

Additional info for this issue: Since Proton 5.13 onwards, Steam Linux Runtime (Soldier) is used to run games in seperate namespaces.

Could somebody distill the knowledge scattered throughout these comments into a simple step by step guide HOWTO correctly execute e.g. VC_redist.x64.exe in the SkyrimSE Steam installation's WINE prefix (because a particular mod requires VC2019 redistributables)? Assume the instructions should be for someone who has never done anything more advanced with Steam Linux than simply installing and running games.