start

startx [ client_options ] [ -- server_options ]

client_options
    Options or arguments passed to the client program (e.g., window manager, desktop environment, or an initial terminal like xterm) that is launched by xinit. These options are specific to the client application being started.

--
    A mandatory separator used to distinguish options intended for the client program from those intended for the X server itself. Any arguments following this separator are passed to the X server.

server_options
    Options or arguments passed directly to the X server program (e.g., Xorg). These can control various aspects of the X server's behavior, such as the display number, screen resolution, color depth, or access control settings.

The startx command is a shell script that serves as a front-end to the xinit program. Its primary purpose is to simplify the process of starting the X Window System graphical environment on a Linux system. It typically reads user-specific configuration files (like ~/.xinitrc and ~/.xserverrc) and system-wide defaults to determine which X server and client (such as a window manager or desktop environment like GNOME or KDE) to launch. While startx historically was a common way to initiate a graphical session directly from the console, modern Linux distributions often utilize display managers (e.g., GDM, LightDM, SDDM) to manage graphical logins and sessions automatically. This makes direct startx usage less frequent for typical daily operation but still valuable for troubleshooting, custom setups, or environments without a display manager. It is important to note that startx is specifically for graphical sessions and is not a general-purpose command for starting background services or regular terminal applications.

The term "start" in Linux is broad and implemented by various commands. startx specifically initiates a graphical X session and is not a universal command for starting any application or service. For system services, systemctl start (on systemd-based systems) or service start (on older SysVinit/Upstart systems) are used. Running a regular application from the terminal simply involves typing its name. startx relies heavily on configuration files (~/.xinitrc, ~/.xserverrc, and system defaults), and its behavior can vary significantly based on their content.

It is crucial to understand that there is no single, universal "start" command in Linux that can be used to initiate any type of process or service. The method for starting something depends on its nature and the system's configuration. The commands used for 'starting' include:

For managing background services or daemons on modern Linux distributions that use systemd (like Debian, Ubuntu, Fedora, CentOS, RHEL), the primary command is
systemctl start service_name
For example, systemctl start nginx.service would start the Nginx web server. On older systems or those using SysVinit/Upstart, the command might be
service service_name start

To start a regular application from the terminal, you typically just type its executable name, e.g., firefox to launch the web browser. To run an application in the background and free up the terminal, you can append an ampersand (&) to the command, e.g., firefox &. For graphical applications, this usually opens a new window.

While startx can initiate an X session, most users log into graphical environments through a Display Manager (e.g., GDM, LightDM, SDDM). These managers handle the complexities of starting the X server, launching the desktop environment, and managing user sessions automatically after login.

The startx command emerged as a convenient wrapper around xinit, simplifying the direct invocation of the X Window System from the console. Its origins are deeply intertwined with the early development of X, providing a user-friendly script to launch the graphical environment before the widespread adoption of graphical login managers (display managers). While it remains a functional and robust tool, particularly for custom or minimal X setups and troubleshooting, its general usage for starting daily graphical sessions has diminished with modern distributions' reliance on sophisticated display manager solutions that automate the login and session startup process.

xinit(1), systemctl(1), service(8), Xorg(1), X(7), display-manager(7)