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name: steam-linux description: This skill should be used when working with Steam on Linux - managing non-Steam game shortcuts, configuring Proton/Wine compatibility, parsing VDF files, or finding Steam paths and prefixes.

Steam Linux Management

Use this skill when modifying Steam shortcuts, configuring Proton, or working with Steam's configuration files on Linux.

Steam Paths

STEAM_ROOT = ~/.local/share/Steam
├── config/
│   ├── config.vdf          # Text VDF - Proton mappings, settings
│   └── libraryfolders.vdf  # Text VDF - Steam library locations
├── steamapps/
│   ├── common/             # Installed games and Proton versions
│   ├── compatdata/         # Proton prefixes (Wine bottles)
│   └── libraryfolders.vdf  # Library paths
└── userdata/{USER_ID}/
    └── config/
        └── shortcuts.vdf   # Binary VDF - Non-Steam game shortcuts

Finding Steam User ID

from pathlib import Path
STEAM_ROOT = Path.home() / ".local/share/Steam"
userdata = STEAM_ROOT / "userdata"
user_id = next((d.name for d in userdata.iterdir() if d.is_dir() and d.name.isdigit()), None)

Finding Steam Library Folders

Parse libraryfolders.vdf (text VDF):

libs = [STEAM_ROOT]
with open(STEAM_ROOT / "steamapps/libraryfolders.vdf") as f:
    for line in f:
        if '"path"' in line:
            path = line.split('"')[3]
            libs.append(Path(path))

Binary VDF Format (shortcuts.vdf)

Non-Steam shortcuts use binary VDF format.

Type Bytes

• 0x00 - Nested object start
• 0x01 - String value
• 0x02 - Int32 value (little-endian)
• 0x08 - Object end

Structure

0x00 "shortcuts" 0x00
  0x00 "0" 0x00           # First shortcut (index)
    0x02 "appid" 0x00 [4 bytes LE int]
    0x01 "AppName" 0x00 "Game Name" 0x00
    0x01 "Exe" 0x00 "\"path/to/exe\"" 0x00
    0x01 "StartDir" 0x00 "\"path/to/dir\"" 0x00
    0x01 "LaunchOptions" 0x00 "options" 0x00
    ...
  0x08                     # End of shortcut
0x08 0x08                  # End of shortcuts, end of root

Parsing Example

See references/vdf-parser.py for complete implementation.

Shortcut App ID Generation

Steam generates app IDs for non-Steam games using CRC32:

import zlib
def generate_app_id(exe_path, app_name):
    key = f'"{exe_path}"{app_name}'
    crc = zlib.crc32(key.encode('utf-8')) & 0xFFFFFFFF
    return crc | 0x80000000

Shortcut Fields

Required fields for a shortcut entry:

{
    'appid': int,           # Generated app ID
    'AppName': str,         # Display name
    'Exe': str,             # Path in quotes: '"path/to/exe"'
    'StartDir': str,        # Working dir in quotes
    'icon': str,            # Icon path (optional)
    'ShortcutPath': str,    # Usually empty
    'LaunchOptions': str,   # Command line args
    'IsHidden': int,        # 0 or 1
    'AllowDesktopConfig': int,
    'AllowOverlay': int,
    'OpenVR': int,
    'Devkit': int,
    'DevkitGameID': str,
    'DevkitOverrideAppID': int,
    'LastPlayTime': int,    # Unix timestamp
    'FlatpakAppID': str,
    'tags': {}              # Nested object for categories
}

Text VDF Format (config.vdf)

Steam's main config uses text VDF format - key-value pairs with tabs.

Proton Compatibility Tool Mapping

Located in config.vdf under CompatToolMapping:

"CompatToolMapping"
{
    "APP_ID"
    {
        "name"      "proton_experimental"
        "config"    ""
        "priority"  "250"
    }
}

Adding Proton Mapping

def add_compat_tool_mapping(app_id, tool="proton_experimental"):
    config_path = STEAM_ROOT / "config/config.vdf"
    with open(config_path, 'r') as f:
        content = f.read()

    # Check if already exists in CompatToolMapping section
    compat_start = content.find('"CompatToolMapping"')
    if compat_start != -1:
        compat_section = content[compat_start:compat_start+5000]
        if f'"{app_id}"' in compat_section:
            return  # Already configured

    # Find insertion point after CompatToolMapping {
    pos = content.find('"CompatToolMapping"')
    brace_pos = content.find('{', pos)

    # Build entry (use chr(9) for tabs to avoid template issues)
    TAB = chr(9)
    NL = chr(10)
    entry = NL + TAB*5 + f'"{app_id}"' + NL
    entry += TAB*5 + '{' + NL
    entry += TAB*6 + '"name"' + TAB*2 + f'"{tool}"' + NL
    entry += TAB*6 + '"config"' + TAB*2 + '""' + NL
    entry += TAB*6 + '"priority"' + TAB*2 + '"250"' + NL
    entry += TAB*5 + '}'

    new_content = content[:brace_pos+1] + entry + content[brace_pos+1:]
    with open(config_path, 'w') as f:
        f.write(new_content)

Proton/Compatdata

Each game/shortcut has a Wine prefix in compatdata:

~/.local/share/Steam/steamapps/compatdata/{APP_ID}/
├── pfx/                    # Wine prefix root
│   └── drive_c/           # C: drive
│       ├── Program Files/
│       ├── Program Files (x86)/
│       └── users/steamuser/
├── version                 # Proton version used
└── config_info            # Configuration metadata

Finding a Game's Prefix

def find_game_prefix(game_name_pattern):
    """Find compatdata prefix containing a specific game/app."""
    for lib in get_steam_libraries():
        compatdata = lib / "steamapps/compatdata"
        if not compatdata.exists():
            continue
        for prefix in compatdata.iterdir():
            # Check for the game in common Windows install locations
            for check_path in [
                prefix / "pfx/drive_c/Program Files" / game_name_pattern,
                prefix / "pfx/drive_c/Program Files (x86)" / game_name_pattern,
            ]:
                if check_path.exists():
                    return prefix
    return None

Sharing Prefixes Between Shortcuts

To make a shortcut use an existing prefix (e.g., for Battle.net games):

LaunchOptions: STEAM_COMPAT_DATA_PATH="/path/to/compatdata/APP_ID" %command% [args]

Proton Versions

Common Proton tool IDs:

• proton_experimental - Proton Experimental
• proton_10 - Proton 10.0
• proton_9 - Proton 9.0

Proton locations:

{LIBRARY}/steamapps/common/Proton - Experimental/proton
{LIBRARY}/steamapps/common/Proton 10.0/proton

Launching Games

Via Steam Protocol

steam steam://rungameid/{APP_ID}
xdg-open steam://rungameid/{APP_ID}

Via Command Line

steam -applaunch {APP_ID}

Note: These require Steam to be running and may not work reliably for non-Steam shortcuts.

Important Notes

1. Close Steam before modifying config files - Steam may overwrite changes
2. Restart Steam after changes - New shortcuts won't appear until restart
3. App IDs for shortcuts - Must use the CRC32-based generation algorithm
4. Quote paths in Exe/StartDir - Always wrap paths in double quotes
5. Template escaping - When using in chezmoi templates, avoid \n, \t, use chr() instead