Mainframe computer systems have a special terminal where the system operator can issue privileged commands to the system, to do things mere mortals can't do, like tell the system you've mounted a tape, or to authorize special privileges. When this is a single, permanent terminal, it's often called the Master Console, or alternatively, Console Commands.
Many video games have a master console as well. In this case, the master console is enabled either by a command-line option or a special key, such as the tilde "~" on US keyboards or "`" on European keyboards (They're in the same position). When the master console is enabled, one can change many of the features of the game, including changing internal variables (such as the weight of gravity), enable special God Mode features, give infinite ammo, or virtually anything the programmers choose to put in the master console subsystem. An inverted usage also existed, by purposefully lowering every player stat to 1 and cranking up the enemies' stat, one can create a Self-Imposed Challenge. Most of the time, these are referred to as Developer Consoles designed to execute commands in order to test game elements without having to use the proper effort and save time, such as noclipping to a particular portion of a map that was edited or giving all of the weapons to test them and they're kept in the game either as a simple cheat system or for people aspiring to create a Game Mod.
Note the term "master console" is being used here to keep from confusing with game consoles, the dedicated hardware used to play games. Should not be confused especially with the Sega Master System console.
Games that have a master console include:
- The Dungeon game for the PDP-11 minicomputer (later modified and released for home microcomputers as the Zork trilogy) had a debugger that could be used to change things, variables and constructs in the game.
- Colossal Cave Adventure had a "MAGIC MODE" command that allowed the game manager, when the game was running on a shared computer such as a mainframe, to restrict times that the game could be played, set the welcome message, and optionally change the password to access magic mode. The bytecode to do this is still present in some PC versions — it's just the "Is this a shared computer?" system call that's Dummied Out.
- The pinball game Balls of Steel has a master console where you can enter cheats. However, if you use the console too many times without entering a valid cheat, the console will be disabled until you reset the game.
- Quake might have been the first FPS to use a drop-down command-line console. The game's configuration files were actually shell scripts for the console, run through during startup just like your autoexec.bat or .bashrc. Sequels and games using a derivative of the engines have similarly accessed console.
- Half-Life, originally based on the Quake engine, continued to include a console on the Source engine games (Half-Life 2 onwards) which allows you to enable or disable certain features. Portal adds additional features to change some of the functionality of the portal gun. And as Half-Life before, other games produced on Source carry on the convention.
- The Unreal series' console added an entry-line pop-up version that did not obscure the screen. Unreal engine games frequently implement chat commands by popping up a command line pre-loaded with a "say" command. In later engines, the drop-down hotkey has migrated to F10.
- Battlezone has probably one of the most powerful consoles out there, capable of doing stuff like "swapping the skybox". In fact, basic console knowledge is required for mappers since the second game's built-in map editor is not exactly user-friendly.
- Several source ports of Doom such as ZDoom, add a Quake-styled drop-down console to access more detailed commands.
- Crysis and CryEngine games feature a console. It's fairly lacking in interesting commands and cheats, but allows heavy customization of the game's graphical and audio settings; particularly useful since the game mauled PCs when it came out. In the Mechwarrior Living Legends Game Mod, the console is the only way to access the handful of secret camouflages, like the "sbaros" blue mosaic camouflage on the Warhammer.
- Everybody Edits, commands start with / and must be typed into chat. Many of these are owner-only, allowing the owner of the world to change settings. However, later updates make commands less necessary with improved GUI and menus.
- The The Elder Scrolls III: Morrowind, Oblivion, and Skyrim, as well as Fallout 3, Fallout4 and Fallout: New Vegas all made use of the Gamebryo engine, and thus, shared a lot of command codes. These games, aside from New Vegas, were also all developed by Bethesda (New Vegas being made by Obsidian Entertainment).
- By contrast, the Mass Effect series does have game manipulative codes entered via a command line, but this unlocked system is not as refined or varied as the one above.
- The Neverwinter Nights series.