# aptitude show gdm
Package: gdm                             
New: yes
State: not installed
Version: 2.20.11-4
Priority: optional
Section: gnome
Maintainer: Debian GNOME Maintainers <pkg-gnome-maintainers@lists.alioth.debian.org>
Uncompressed Size: 17.2 M
Depends: libart-2.0-2 (>= 2.3.18), libatk1.0-0 (>= 1.29.3), libattr1 (>= 2.4.41-1), libc6
         (>= 2.3.6-6~), libcairo2 (>= 1.2.4), libdbus-1-3 (>= 1.0.2), libdbus-glib-1-2 (>=
         0.78), libdmx1, libfontconfig1 (>= 2.8.0), libfreetype6 (>= 2.2.1), libglade2-0
         (>= 1:2.6.1), libglib2.0-0 (>= 2.24.0), libgnomecanvas2-0 (>= 2.11.1), libgtk2.0-0
         (>= 2.18.0), libpam0g (>= 0.99.7.1), libpango1.0-0 (>= 1.14.0), librsvg2-2 (>=
         2.26.0), libselinux1 (>= 1.32), libwrap0 (>= 7.6-4~), libx11-6, libxau6,
         libxdmcp6, libxext6, libxi6, libxinerama1, libxml2 (>= 2.7.4), debconf (>= 0.5) |
         debconf-2.0, adduser, libpam-modules (>= 0.72-1), libpam-runtime (>= 0.76-13.1),
         gnome-session | x-session-manager | x-window-manager | x-terminal-emulator, gksu
         (>= 1.0.7), lsb-base (>= 3.2-14), librsvg2-common
Recommends: whiptail | dialog, zenity, gdm-themes, xserver-xephyr | xnest, xserver-xorg
Suggests: locales, pm-utils, libpam-gnome-keyring
Conflicts: fast-user-switch-applet (< 2.17.4), gnome-panel (< 2.19.2), gnome-screensaver (<
           2.17.7), gnome-session (< 2.19.2)
Provides: x-display-manager
Description: GNOME Display Manager
 gdm provides the equivalent of a "login:" prompt for X displays- it pops up a login window
 and starts an X session. 
 
 It provides all the functionality of xdm, including XDMCP support for managing remote
 displays. 
 
 The greeting window is written using the GNOME libraries and hence looks like a GNOME
 application- even to the extent of supporting themes! By default, the greeter is run as an
 unprivileged user for security.

# sudo pacman -Si gdm
Repository     : extra
Name           : gdm
Version        : 3.2.1.1-1
URL            : http://www.gnome.org
Licenses       : GPL
Groups         : gnome-extra
Provides       : None
Depends On     : libcanberra  libxklavier  gnome-session  gnome-settings-daemon  metacity  upower  accountsservice
                 consolekit  xorg-xrdb  nss
Optional Deps  : gnome-shell: new login interface
Conflicts With : None
Replaces       : None
Download Size  : 917.06 K
Installed Size : 6659.00 K
Packager       : Jan Alexander Steffens (heftig) <jan.steffens@gmail.com>
Architecture   : x86_64
Build Date     : Wed 19 Oct 2011 07:59:55 PM EEST
MD5 Sum        : d6d9d87617eb3e296b7b6379ac29d07f
Description    : Gnome Display Manager (a reimplementation of xdm)

Targets (24): iso-codes-3.29-1  libxklavier-5.1-1  libplist-1.4-1  usbmuxd-1.0.7-2  libimobiledevice-1.1.1-2
              upower-0.9.15-1  consolekit-0.4.5-1  json-glib-0.14.2-1  gnome-session-3.2.1-1  libgnomekbd-3.2.0-1
              gnome-desktop-3.2.1-1  libcanberra-pulse-0.28-2  rtkit-0.10-2  fftw-3.3-1  pulseaudio-1.1-1
              alsa-plugins-1.0.24-3  pulseaudio-alsa-1-2  gnome-settings-daemon-3.2.2-1  zenity-3.2.0-1  libxres-1.0.5-1
              libwnck-2.30.7-1  metacity-2.34.1-1  accountsservice-0.6.15-1  gdm-3.2.1.1-1