There is only one recommended way to install Cygwin, which is to use the GUI installer ``Cygwin Setup''. It is flexible and easy to use. You can pick and choose the packages you wish to install, and update them individually. Full source code is available for all packages and tools. More information on using Cygwin Setup may be found at http://cygwin.com/cygwin-ug-net/setup-net.html.

If you do it any other way, you're on your own! That said, keep in mind that the GUI installer is a "work in progress", so there might be a few difficulties, especially if you are behind a firewall or have other specific requirements. If something doesn't work right for you, and it's not covered here or in the latest development snapshot at http://cygwin.com/snapshots/, then by all means report it to the mailing list.

For a searchable list of packages that can be installed with Cygwin, see http://cygwin.com/packages/.

The Cygwin Setup program is designed to be interactive, but there are a few different ways to automate it. If you are deploying to multiple systems, the best way is to run through a full installation once, saving the entire downloaded package tree. Then, on target systems, run setup.exe as a "Local Install" pointed at your downloaded package tree. You could do this non-interactively with the command line options setup.exe -q -L -l x:\cygwin-local\, where your downloaded package tree is in x:\cygwin-local\ (see the next FAQ for an explanation of those options.)

For other options, search the mailing lists with terms such as cygwin automated setup or automated cygwin install.

Yes, the full listing is written to the setup.log file when you run setup.exe --help. The current options are:

Command Line Options:
 -D --download                          Download from internet
 -L --local-install                     Install from local directory
 -s --site                              Download site
 -R --root                              Root installation directory
 -q --quiet-mode                        Unattended setup mode
 -h --help                              print help
 -l --local-package-dir                 Local package directory
 -r --no-replaceonreboot                Disable replacing in-use files on next
                                        reboot.
 -n --no-shortcuts                      Disable creation of desktop and start
                                        menu shortcuts
 -N --no-startmenu                      Disable creation of start menu shortcut
 -d --no-desktop                        Disable creation of desktop shortcut
 -A --disable-buggy-antivirus           Disable known or suspected buggy anti
                                        virus software packages during
                                        execution.

The Cygwin Setup program will prompt you for a "root" directory. The default is C:\cygwin, but you can change it. You are urged not to choose something like C:\ (the root directory on the system drive) for your Cygwin root. If you do, then critical Cygwin system directories like etc, lib and bin could easily be corrupted by other (non-Cygwin) applications or packages that use \etc, \lib or \bin. Perhaps there is no conflict now, but who knows what you might install in the future? It's also just good common sense to segregate your Cygwin "filesystems" from the rest of your Windows system disk.

(In the past, there had been genuine bugs that would cause problems for people who installed in C:\, but we believe those are gone now.)

Cygwin Setup can be used to install any packages that are on a Cygwin mirror, which usually includes one version previous to the current one. The complete list may be searched at http://cygwin.com/packages/. There is no complete archive of older packages. If you have a problem with the current version of a Cygwin package, please report it to the mailing list using the guidelines at http://cygwin.com/problems.html.

That said, if you really need an older package, you may be able to find an outdated or archival mirror by searching the web for an old package version (for example, gcc2-2.95.3-10-src.tar.bz2), but keep in mind that this older version will not be supported by the mailing list and that installing the older version will not help improve Cygwin.

When you upgrade an existing older Cygwin installation to Cygwin 1.7, your old system mount points (stored in the HKEY_LOCAL_MACHINE branch of your registry) are read by a script and the /etc/fstab file is generated from these entries. No such automatism exists for the user mount points formerly stored in the HKEY_CURRENT_USER branch of the registry. There's a bash script for your convenience, which creates a user-specific /etc/fstab/${USER} file for you, called /bin/copy-user-registry-fstab. For more information on the new fstab files see the User's Guide at http://cygwin.com/cygwin-ug-net/using.html#mount-table

Unlikely. Unless you can confirm it, please don't report it to the mailing list. Anti-virus products have been known to detect false positives when extracting compressed tar archives. If this causes problems for you, consider disabling your anti-virus software when running setup. Read the next entry for a fairly safe way to do this.

Both Network Associates (formerly McAfee) and Norton anti-virus products have been reported to "hang" when extracting Cygwin tar archives. If this happens to you, consider disabling your anti-virus software when running Cygwin Setup. The following procedure should be a fairly safe way to do that:

This should be safe, but only if Cygwin Setup is not substituted by something malicious, and no mirror has been compromised.

See also http://cygwin.com/faq/faq.using.html#faq.using.bloda for a list of applications that have been known, at one time or another, to interfere with the normal functioning of Cygwin.

When using Cygwin Setup for the first time, the default is to install a minimal subset of all available packages. If you want anything beyond that, you will have to select it explicitly. See http://cygwin.com/packages/ for a searchable list of available packages, or use cygcheck -p as described in the Cygwin User's Guide at http://cygwin.com/cygwin-ug-net/using-utils.html#cygcheck.

If you want to build programs, of course you'll need gcc, binutils, make and probably other packages from the ``Devel'' category. Text editors can be found under ``Editors''.

Long ago, the default was to install everything, much to the irritation of most users. Now the default is to install only a basic core of packages. Cygwin Setup is designed to make it easy to browse categories and select what you want to install or omit from those categories. It's also easy to install everything:

This procedure only works for packages that are currently available. There is no way to tell Cygwin Setup to install all packages by default from now on. As new packages become available that would not be installed by default, you have to repeat the above procedure to get them.

In general, a better method (in my opinion), is to:

That depends, obviously, on what you've chosen to download and install. A full installation today is probably larger than 1 GB installed, not including the package archives themselves nor the source code.

After installation, the package archives remain in your ``Local Package Directory'', by default the location of setup.exe. You may conserve disk space by deleting the subdirectories there. These directories will have very weird looking names, being encoded with their URLs (named ftp%3a%2f...).

Of course, you can keep them around in case you want to reinstall a package. If you want to clean out only the outdated packages, Michael Chase has written a script called clean_setup.pl, available at ftp://cygwin.com/pub/cygwin/unsupported/clean_setup.pl.

Detailed logs of the most recent Cygwin Setup session can be found in /var/log/setup.log.full and less verbose information about prior actions is in /var/log/setup.log.

First, make sure that you are using the latest version of Cygwin Setup. The latest version is always available from the 'Install Cygwin now' link on the Cygwin Home Page at http://cygwin.com/.

If you are downloading from the Internet, setup will fail if it cannot download the list of mirrors at http://cygwin.com/mirrors.html. It could be that the network is too busy. Something similar could be the cause of a download site not working. Try another mirror, or try again later.

If setup refuses to download a package that you know needs to be upgraded, try deleting that package's entry from /etc/setup. If you are reacting quickly to an announcement on the mailing list, it could be that the mirror you are using doesn't have the latest copy yet. Try another mirror, or try again tomorrow.

If setup has otherwise behaved strangely, check the files setup.log and setup.log.full in /var/log (C:\cygwin\var\log by default). It may provide some clues as to what went wrong and why.

If you're still baffled, search the Cygwin mailing list for clues. Others may have the same problem, and a solution may be posted there. If that search proves fruitless, send a query to the Cygwin mailing list. You must provide complete details in your query: version of setup, options you selected, contents of setup.log and setup.log.full, what happened that wasn't supposed to happen, etc.

The problem is that Terminal Server machines do some compatibility checks when running applications which are not marked as "Terminal Server-aware", and this compatibility check seems to be buggy, leaving parts of the application in a non-executable state. Curious enough, this only happens if DEP (Data Execution Prevention) is turned on for all applications.

So far, only few Cygwin packages have their binaries marked as TS-aware, which means there's a good chance that the postinstall scripts during the installation will break, and that after installation you can't start a shell, etc.

So, for the time being, here's how you install Cygwin on a Terminal Server. First, switch DEP to "Turn on DEP for essential Windows programs and services only" and reboot the machine. Then install via setup.exe. You can leave it at that and run the Terminal Server in the aforementioned DEP setting. Or use the peflags tool from the rebase package to set the TS-aware flag in all executables, switch DEP back to "Turn on DEP for all programs and services except [...]" and reboot again. However, please keep in mind that a package update might re-install a binary with the TS-aware flag switched off again. So you will have to re-use the peflags utility once in a while.

Most definitely yes! UNIX shells (and thus Cygwin) use the space character as a word delimiter. Under certain circumstances, it is possible to get around this with various shell quoting mechanisms, but you are much better off if you can avoid the problem entirely.

On Windows NT/2000/XP you have two choices:

On Windows 95/98/ME you can create a new user and run mkpasswd, or you can delete the offending entry from /etc/passwd. Cygwin will then use the name in the default entry with uid 500.

When starting Cygwin from Windows, HOME is determined as follows in order of decreasing priority:

When using Cygwin from the network (telnet, ssh,...), HOME is set from /etc/passwd.

If your HOME is set to a value such as /cygdrive/c, it is likely that it was set in Windows. Start a DOS Command Window and type "set HOME" to verify if this is the case.

Access to shared drives is often restricted when starting from the network, thus Domain users may wish to have a different HOME in the Windows environment (on shared drive) than in /etc/passwd (on local drive). Note that ssh only considers /etc/passwd, disregarding HOME.

Run Cygwin Setup as you would to install packages. In the list of packages to install, browse the relevant category or click on the ``View'' button to get a full listing. Click on the cycle glyph until the action reads ``Uninstall''. Proceed by clicking ``Next''.

Setup has no automatic uninstall facility. The recommended method to remove all of Cygwin is as follows:

First, are you sure you want to do this? Snapshots are risky. They have not been tested. Use them only if there is a feature or bugfix that you need to try, and you are willing to deal with any problems, or at the request of a Cygwin developer.

You should generally install the full cygwin-inst-YYYYMMDD.tar.bz2 update, rather than just the DLL, otherwise some components may be out of sync.

You cannot use Cygwin Setup to install a snapshot.

First, you will need to download the snapshot from the snapshots page at http://cygwin.com/snapshots/. Note the directory where you saved the snapshot tarball.

Before installing a snapshot, you must first Close all Cygwin applications, including shells and services (e.g., inetd, sshd). You will not be able to replace cygwin1.dll if any Cygwin process is running. You may have to restart Windows to clear the DLL from memory (beware of automatic service startup).

Most of the downloaded snapshot can be installed using tar. Cygwin tar won't be able to update /usr/bin/cygwin1.dll (because it's used by tar itself), but it should succeed with everything else. If you are only installing the DLL snapshot, skip the first tar command. Open a bash shell (it should be the only running Cygwin process) and issue the following commands:

	/bin/tar -C/ -jxvf /posix/path/to/cygwin-inst-YYYYMMDD.tar.bz2 --exclude=usr/bin/cygwin1.dll
	/bin/tar -C/tmp -jxvf /posix/path/to/cygwin-inst-YYYYMMDD.tar.bz2 usr/bin/cygwin1.dll

Exit the bash shell, and use Explorer or the Windows command shell to first rename C:\cygwin\bin\cygwin1.dll to C:\cygwin\bin\cygwin1-prev.dll and then move C:\cygwin\tmp\usr\bin\cygwin1.dll to C:\cygwin\bin\cygwin1.dll (assuming you installed Cygwin in C:\cygwin).

The operative word in trying the snapshots is "trying". If you notice a problem with the snapshot that was not present in the release DLL (what we call a "regression"), please report it to the Cygwin mailing list (see http://cygwin.com/problems.html for problem reporting guidelines). If you wish to go back to the older version of the DLL, again, close all Cygwin processes, delete C:\cygwin\bin\cygwin1.dll, and rename C:\cygwin\bin\cygwin1-prev.dll back to C:\cygwin\bin\cygwin1.dll (again assuming that your "/" is C:\cygwin). To restore the rest of the snapshot files, reinstall the "cygwin" package using Setup.

NO. Cygwin Setup cannot do this for you. Use a tool designed for this purpose. See http://rsync.samba.org/, http://wget.sunsite.dk/ for utilities that can do this for you. For more information on setting up a custom Cygwin package server, see the Cygwin Setup homepage at http://sourceware.org/cygwin-apps/setup.html.

While some users have successfully done this, for example Indiana University's XLiveCD http://xlivecd.indiana.edu/, there is no easy way to do it. Full instructions for constructing a portable Cygwin on CD by hand can be found on the mailing list at http://www.cygwin.com/ml/cygwin/2003-07/msg01117.html (Thanks to fergus at bonhard dot uklinux dot net for these instructions.) Please note that these instructions are rather old and are referring to the somewhat different setup of a Cygwin 1.5.x release. As soon as somebody set this up for Cygwin 1.7, we might add this information here.

Since Cygwin 1.7, there's nothing important in the registry anymore, except for the installation directory information stored there for the sake of setup.exe. There's nothing left to manipulate anymore.