SLiM (display manager)

SLiM (display manager)
Name	SLiM
Operating system	Unix-like
Platform	X11
Genre	Display manager
License	MIT License

SLiM (display manager) is a lightweight X11 graphical login manager intended for Unix-like operating systems. It provides a minimal, fast session chooser and user authentication front end for desktop environments such as KDE, GNOME, Xfce, and LXDE, and for window managers like Openbox, i3, Awesome (window manager), and Fluxbox. SLiM aims to be small and unobtrusive while interoperating with display servers and session frameworks associated with projects such as X.Org, Wayland (as a compatibility consideration), and systemd.

Overview

SLiM serves as a display manager alternative to heavier projects such as GDM (GNOME Display Manager), SDDM, and LightDM, targeting users of distributions like Debian, Ubuntu, Arch Linux, Fedora, Gentoo, and Void Linux. Written in the C programming language and distributed under permissive licensing, SLiM performs user authentication typically via PAM modules like those used by PAM (Pluggable Authentication Modules), and delegates session initialization to scripts compatible with Xsession and desktop launching conventions used by Freedesktop.org. Its minimalist philosophy appeals to users of lightweight environments such as LXQt and retro window managers including twm.

Features

SLiM implements features expected of a display manager while keeping resource usage low, similar in intent to nodm and xdm. Typical features include: - Session selection supporting desktop entries from Desktop Entry Specification and session lists used by XDG Base Directory Specification, allowing choices like MATE (software), Cinnamon (desktop environment), and Enlightenment (software). - User list and manual username entry compatible with authentication provided by PAM (Pluggable Authentication Modules), and integration points for authentication backends used by LDAP and Kerberos (protocol). - Configurable autologin and timed login behaviors comparable to mechanisms in LightDM and SDDM implementations, and support for accessibility considerations used by Orca (assistive technology) when launched by session scripts. - Session management and logout/shutdown control that cooperates with init systems such as systemd, OpenRC, and runit through standard shutdown utilities.

Configuration and Customization

SLiM is configured via a single plaintext configuration file typically located in /etc, following conventions similar to configuration approaches used by Xwrapper.config and lightdm.conf. Administrators can set defaults for session, language, accessibility, and autologin behavior comparable to settings available in GDM (GNOME Display Manager) and SDDM. Custom scripts invoked at session start and stop follow patterns used by Xsession and can call utilities from ConsoleKit or logind when coordinating with power management daemons like UPower. The configuration supports localization with locale identifiers used by gettext and environment variables standardized by POSIX.

Themes and Appearance

The visual presentation of SLiM relies on themes composed of images, fonts, and CSS-like layout directives, a scheme similar in concept to theming mechanisms used by GTK+ and Qt (software) applications. Themes can reference assets from icon sets popularized by projects such as Tango Desktop Project and Icon Theme Specification, and can be adapted to match desktop environments like KDE Plasma or GNOME Shell aesthetics. Community-contributed themes are often shared on platforms associated with distributions and projects such as GitHub, GitLab, and forums used by Arch Linux and Ubuntu communities.

Compatibility and Integration

SLiM operates primarily with the X.Org server and X11 toolkits, enabling integration with compositors and window systems that rely on X11 backwards compatibility. While Wayland-native compositors like Weston and Sway favor Wayland-native greeters, SLiM remains relevant on systems where X11 session startup is required, interoperating with session launchers used by Xfce, LXDE, and display environments tied to XDMCP for remote session management alongside servers like Xpra and XDM (X Display Manager). Integration with authentication and session management services mirrors practices used by LightDM and GDM (GNOME Display Manager).

Development and Maintenance

Historically maintained by contributors in open-source communities and hosted in repositories on platforms such as SourceForge and GitHub, SLiM's development model reflects that of small utility projects maintained by volunteers similar to dmenu and i3wm. Maintenance depends on community patches, issue trackers, and packaging by distribution maintainers for Debian, Fedora, Arch Linux, and Gentoo. Discussions about feature requests, security hardening, and compatibility with modern init systems and display servers occur in mailing lists and issue trackers like those used by freedesktop.org projects and distribution-specific bug trackers.

Category:Display managers