On a Linux or Mac system, you must have superuser privileges to perform a PostgreSQL installation. To perform an installation on a Windows system, you must have administrator privileges.If you are installing PostgreSQL into a Windows system that is configured with User Account Control (UAC) enabled, you can assume sufficient privileges to invoke the graphical installer by right clicking on the name of the installer and selecting Run as administrator from the context menu. If prompted, enter an administrator password to continue.You must install xterm, konsole, or gnome-terminal before executing any console-based program installed by the PostgreSQL installer.Before installing PostgreSQL on a system that is running SELinux, you must set SELinux to permissive mode.The following example works on Redhat Enterprise Linux, Fedora Core or CentOS distributions. Use comparable commands that are compatible with your Linux distribution to set SELinux to permissive mode during installation and return it to enforcing mode when installation is complete.Before installing PostgreSQL, set SELinux to permissive mode with the command:When the installation is complete, return SELinux to enforcing mode with the command:Be sure to apply Windows operating system updates before invoking the PostgreSQL installer. If (during the installation process) the installer encounters errors, exit the installation, and ensure that your version of Windows is up-to-date before restarting the installer.PostgreSQL installation on Mac OS X differs slightly from other platforms as the distribution is in a different format, and some additional configuration may be required.The Mac OS X installer is an App Bundle (a set of files and directories in a prescribed format). To ensure the App Bundle can be downloaded, it is packaged inside a disk image (.dmg) file. To extract the installer, simply mount the disk image and copy the installer to the desired location, or run it directly from the disk image.By default, Mac OS X ships with shared memory settings that are too low for running PostgreSQL. The installer will detect this, and if possible, reconfigure shared memory and then prompt you to reboot the system and rerun the PostgreSQL installer. For more information, please see the README file in the distribution disk image.