To install the Cygwin net release, go to http://cygwin.com/ and run either setup-x86.exe to install the 32 bit version of Cygwin, or setup-x86_64.exe to install the 64 bit version of Cygwin. This will download a GUI installer which can be run to download a complete cygwin installation via the internet. Follow the instructions on each screen to install Cygwin. For easier reading the installer is called setup.exe throughout the following sections. This refers likewise to both installer applications, setup-x86.exe for 32 bit, as well as setup-x86_64.exe for 64 bit. Apart from the target architecture they are the same thing. The setup.exe installer is designed to be easy for new users to understand while remaining flexible for the experienced. The volunteer development team is constantly working on setup.exe; before requesting a new feature, check the wishlist in the CVS README . It may already be present in the CVS version! On Windows Vista and later, setup.exe will check by default if it runs with administrative privileges and, if not, will try to elevate the process. If you want to avoid this behaviour and install under an unprivileged account just for your own usage, run setup.exe with the --no-admin option. Since the default value for each option is the logical choice for most installations, you can get a working minimal Cygwin environment installed by simply clicking the Next button at each page. The only exception to this is choosing a Cygwin mirror, which you can choose by experimenting with those listed at http://cygwin.com/mirrors.html . For more details about each of page of the setup.exe installation, read on below. Please note that this guide assumes that you have a basic understanding of Unix (or a Unix-like OS). If you are new to Unix, you will also want to make use of other resources. Cygwin uses packages to manage installing various software. When the default Install from Internet option is chosen, setup.exe creates a local directory to store the packages before actually installing the contents. Download from Internet performs only the first part (storing the packages locally), while Install from Local Directory performs only the second (installing the contents of the packages). The Download from Internet option is mainly for creating a base Cygwin package tree on one computer for installation on several machines with Install from Local Directory; copy the entire local package tree to another machine with the directory tree intact. For example, you might create a C:\cache\ directory and place setup.exe in it. Run setup.exe to Install from Internet or Download from Internet, then copy the whole C:\cache\ to each machine and instead choose Install from Local Directory. Though this provides some basic mirroring functionality, if you are managing a large Cygwin installation, to keep up to date we recommend using a mirroring tool such as wget. A helpful user on the Cygwin mailing list created a simple demonstration script to accomplish this; search the list for mkcygwget for ideas. The Root Directory for Cygwin (default C:\cygwin) will become / within your Cygwin installation. You must have write access to the parent directory, and any ACLs on the parent directory will determine access to installed files. The Install For options of All Users or Just Me should always be left on the default All Users, unless you do not have write access to HKEY_LOCAL_MACHINE in the registry or the All Users Start Menu. This is true even if you are the only user planning to use Cygwin on the machine. Selecting Just Me will cause problems for programs such as crond and sshd. If you do not have the necessary permissions, but still want to use these programs, consult the Cygwin mailing list archives about others' experiences. The Local Package Directory is the cache where setup.exe stores the packages before they are installed. The cache must not be the same folder as the Cygwin root. Within the cache, a separate directory is created for each Cygwin mirror, which allows setup.exe to use multiple mirrors and custom packages. After installing Cygwin, the cache is no longer necessary, but you may want to retain the packages as backups, for installing Cygwin to another system, or in case you need to reinstall a package. The Direct Connection method of downloading will directly download the packages, while the IE5 method will leverage your IE5 cache for performance. If your organisation uses a proxy server or auto-configuration scripts, the IE5 method also uses these settings. If you have a proxy server, you can manually type it into the Use Proxy section. Unfortunately, setup.exe does not currently support password authorization for proxy servers. Since there is no way of knowing from where you will be downloading Cygwin, you need to choose at least one mirror site. Cygwin mirrors are geographically distributed around the world; check the list at http://cygwin.com/mirrors.html to find one near you. You can select multiple mirrors by holding down CTRL and clicking on each one. If you have the URL of an unlisted mirror (for example, if your organization has an internal Cygwin mirror) you can add it. For each selected mirror site, setup.exe downloads a small text file called setup.bz2 that contains a list of packages available from that site along with some basic information about each package which setup.exe parses and uses to create the chooser window. For details about the format of this file, see the setup.exe homepage. The chooser is the most complex part of setup.exe. Packages are grouped into categories, and one package may belong to multiple categories (assigned by the volunteer package maintainer). Each package can be found under any of those categories in the hierarchical chooser view. By default, setup.exe will install only the packages in the Base category and their dependencies, resulting in a minimal Cygwin installation. However, this will not include many commonly used tools such as gcc (which you will find in the Devel category). Since setup.exe automatically selects dependencies, be careful not to unselect any required packages. In particular, everything in the Base category is required. You can change setup.exe's view style, which is helpful if you know the name of a package you want to install but not which category it is in. Click on the View button and it will rotate between Category (the default), Full (all packages), and Pending (only packages to be installed, removed or upgraded). If you are familiar with Unix, you will probably want to at least glance through the Full listing for your favorite tools. Once you have an existing Cygwin installation, the setup.exe chooser is also used to manage your Cygwin installation. Information on installed packages is kept in the /etc/setup/ directory of your Cygwin installation; if setup.exe cannot find this directory it will act as if you have no Cygwin installation. If setup.exe finds a newer version of an installed package available, it will automatically mark it to be upgraded. To Uninstall, Reinstall, or get the Source for an existing package, click on Keep to toggle it. Also, to avoid the need to reboot after upgrading, make sure to close all Cygwin windows and stop all Cygwin processes before setup.exe begins to install the upgraded package. To avoid unintentionally upgrading, use the Pending view to see which packages have been marked for upgrading. If you don't want to upgrade a package, click on the new version number to toggle it until it says Keep. All packages can be set to stay at the installed version by pressing the Keep button in the top right part of the chooser window. A previous version of each package is usually available, in case downgrading is required to avoid a serious bug in the current version of the package. Packages also occasionally have testing (or "experimental") versions available. Previous and experimental versions can be chosen by clicking on the package's New column until the required version appears. All available experimental packages can be selected by pressing the Exp in the top right part of the chooser window. Be warned, however, that the next time you run setup.exe it will try to replace all old or experimental versions with the current version, unless told otherwise. First, setup.exe will download all selected packages to the local directory chosen earlier. Before installing, setup.exe performs a checksum on each package. If the local directory is a slow medium (such as a network drive) this can take a long time. During the download and installation, setup.exe shows progress bars for the current task and total remaining disk space. You may choose to install "Cygwin Terminal" shortcuts on the Desktop and/or Start Menu. These shortcuts run mintty, which will start your default shell as specified in /etc/passwd. Last of all, setup.exe will run any post-install scripts to finish correctly setting up installed packages. Since each script is run separately, several windows may pop up. If you are interested in what is being done, see the Cygwin Package Contributor's Guide at http://cygwin.com/setup.html When the last post-install script is completed, setup.exe will display a box announcing the completion. A few packages, such as the OpenSSH server, require some manual site-specific configuration. Relevant documentation can be found in the /usr/doc/Cygwin/ or /usr/share/doc/Cygwin/ directory. Unfortunately, the complex setup process means that odd problems can occur. If you're having trouble downloading packages, it may be network congestion, so try a different mirror and/or a different protocol (i.e., HTTP instead of FTP). If you notice something is not working after running setup, you can check the setup.exe log file at /var/log/setup.log.full. Make a backup of this file before running setup.exe again, and follow the steps for Reporting Problems with Cygwin.