I'd like to launch a proton app installed via steam but without using steam.

the point being I can make my own command-line launcher and pass parameters etc...

since I'm entirely new to this I don't know by which horn to grab the bull.

will I be able to course through steam's lib or will I be forced to install my own separate version of proton?

Here's the system info steam gathered of my system :

Computer Information:

    Manufacturer:  Unknown

    Model:  Unknown

    Form Factor: Desktop

    No Touch Input Detected



Processor Information:

    CPU Vendor:  GenuineIntel

    CPU Brand:         Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz

    CPU Family:  0x6

    CPU Model:  0x2d

    CPU Stepping:  0x7

    CPU Type:  0x0

    Speed:  3800 Mhz

    12 logical processors

    6 physical processors

    HyperThreading:  Supported

    FCMOV:  Supported

    SSE2:  Supported

    SSE3:  Supported

    SSSE3:  Supported

    SSE4a:  Unsupported

    SSE41:  Supported

    SSE42:  Supported

    AES:  Supported

    AVX:  Supported

    CMPXCHG16B:  Supported

    LAHF/SAHF:  Supported

    PrefetchW:  Unsupported



Operating System Version:

    Ubuntu 18.04.1 LTS (64 bit)

    Kernel Name:  Linux

    Kernel Version:  4.15.0-33-generic

    X Server Vendor:  The X.Org Foundation

    X Server Release:  11906000

    X Window Manager:  GNOME Shell

    Steam Runtime Version:  steam-runtime-beta-release_2018-06-14



Video Card:

    Driver:  NVIDIA Corporation GeForce GTX 760/PCIe/SSE2

    Driver Version:  4.6.0 NVIDIA 390.48

    OpenGL Version: 4.6

    Desktop Color Depth: 24 bits per pixel

    Monitor Refresh Rate: 60 Hz

    VendorID:  0x10de

    DeviceID:  0x1187

    Revision Not Detected

    Number of Monitors:  2

    Number of Logical Video Cards:  1

    Primary Display Resolution:  1920 x 1080

    Desktop Resolution: 1920 x 1080

    Primary Display Size: 20.04" x 11.26" (22.95" diag)

                                            50.9cm x 28.6cm (58.3cm diag)

    Primary Bus: PCI Express 16x

    Primary VRAM: 2048 MB

    Supported MSAA Modes:  2x 4x 8x 16x 



Sound card:

    Audio device: Realtek ALC898



Memory:

    RAM:  15988 Mb



Miscellaneous:

    UI Language:  English

    LANG:  en_US.UTF-8

    Total Hard Disk Space Available:  491396 Mb

    Largest Free Hard Disk Block:  250110 Mb

    VR Headset: None detected



Recent Failure Reports:

The specific game I'm trying to run is Supreme Commander Forged Alliance and it runs fine via steam.

I don't know why people have been giving it garbage steam play reports on the steam play compatibility site but personally; it runs perfectly:

https://spcr.netlify.com/app/9420

all I have to do is press alt-F4 two times and wait a lot to trick the main menu into showing up and past the main menu there are no bugs at all the in-game experience is fluid and stable.

but yeah, that game's entire online community is on FAF not on steam, both FAF python and FAF java run naively on Linux nowadays for the final key is getting java-FAF to make the correct proton calls to Forged Alliance for the game to fully work :)

Guide to get to where I'm at :

To install FAF :

cd /faf

and run FAF :

downlords-faf-client

or

./downlords-faf-client

now you should have FAF started. If you do not have an account you may create one.

after this, you can go into FAF's settings and there you can configure run folder and run arguments for FA.

Update :

I've since made a guide for how to set up FAF : https://www.youtube.com/watch?v=Rv3ZXA4FNFk