An introduction to Cygwin

1
An introduction to Cygwin
Booth Engineering Center for Advanced Technology
(BECAT) Seminar

• Lili He

2
What is Cygwin?

• Cygwin GNU Cygnus Windows.
• It is a collection of tools to allow Windows to
  act like a Unix/Linux system.
• A DLL (cywin1.dll) acts as a Linux API emulation
  layer to provide substantial Linux API
  functionality
• A collection of tools provide Linux-look and
  feel. The Cygwin tools are ports of the popular
  GNU development tools for Microsoft Windows.

3
Why Use Cygwin/X?

• It provides an X server for Windows clients.
• It allows you to run X programs on remote hosts
  (Unix/Linux systems) and routes the display to
  your Windows desktop.
• It is similar to Hummingbird Exceed, while it is
  free!

4
What Versions of Windows Are Supported?

• Cygwin can run on almost all modern 32 bit
  versions of Windows
• This includes Windows 95/98/ME/NT/2000/XP, but
  except for Windows CE.
• Cygwin will behave differently, and exhibit
  different limitations, on the various versions of
  Windows, since it can only do as much as the
  underlying OS supports.

5
How Much Space Does Cygwin Require?

• It depends on what have been chosen to download
  and install.
• A full installation is probably larger than 800MB
  installed, not including the package archives
  themselves nor the source code.

6
Download Source

• Go to http//cygwin.com/ and click on "Install
  Cygwin Now!.
• This is the most up-to-date version of Cygwin.
• To find the version of the Cygwin DLL installed,
  use uname' as on Linux or cygcheck'.
• Must log in as an administrator user.

7
Installation Options

• Install from Internet creates a local directory
  to store the packages and then installs the
  contents.
• Download from Internet stores the packages
  locally.
• Install from Local Directory installs the
  contents of the packages.

8
Installation Options

• Always choose Install for All Users, 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.
• The Default Text File Type should be left on
  Unix (that is, \n), unless you have a very good
  reason to switch it to DOS (that is, \r\n).

9
Select Root Directory

• Youd better not select something like C\' (the
  root directory on the system drive) for the
  Cygwin root.
• Otherwise, 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'.

10
Select Local Package Directory

• The Local Package Directory is the cache where
  setup.exe stores the packages before they are
  installed.
• It must not be the same folder as the Cygwin
  root. After installing, it is no longer
  necessary, but it may be retained as backups.

11
Select Connection Method

• The Direct Connection method of downloading will
  directly download the packages.

12
Select Mirrors

• At least one mirror site should be chosen.
• Cygwin mirrors are geographically distributed
  around the world http//cygwin.com/mirrors.html
• Multiple mirrors can be selected by holding down
  CTRL and clicking on each one. (http//www.mirrors
  ervice.org http//mirror.mcs.anl.gov are
  recommended)

13
Select Packages

• A chooser window that contains a list and basic
  information of packages will be available from
  mirror sites.
• Packages are grouped into categories.
• A minimal Cygwin installation will only includes
  the packages in the Base category and their
  dependencies by default.

14
Select Packages

• To install Cygwin/X, scroll down to "X11" in the
  "Category" column and click on the word
  "Default", which should then change to "Install".

15
Select Packages

• Openssh could also be installed. It is optional.
• Change View to Full and scroll down until you
  see "openssh" in the "Package, check it to
  install.

16
Download and Installation Progress

• During the download and installation, progress
  bars will be shown for the current task and total
  remaining disk space.

17
Complete Installation

• Shortcuts on the Desktop and/or Start Menu could
  be chosen to install.
• Finally, setup.exe will run any post-install
  scripts to finish correctly setting up installed
  packages.

18
Environment Variables

• The safest way to launch bash initially is to use
  cygwin.bat file provided where the most important
  ones are set before bash in launched.
• CYGWIN variable is used to configure many global
  settings for the Cygwin runtime system.
• Initially you can leave CYGWIN unset or set it to
  tty (e.g. to support job control with Z etc...)
  by using
• C\gt set CYGWINtty notitle glob

19
Environment Variables

• The PATH environment variable is used by Cygwin
  applications as a list of directories to search
  for executable files to run.
• Set it so that it contains at least the
  root\cygwin\bin directory.
• The HOME environment variable is used by many
  programs to determine the location of your home
  directory.
• Set it to point to your home directory before
  launching bash.

20
Customize Bash

• To set bash up so that cut and paste work
  properly, make sure that "Quick Edit" is checked
  under "Properties" of the window, then on the
  Options" tab.

21
What if Setup Fails?

• Make sure that the latest version of Cygwin Setup
  is used.
• The fails of not download the list of mirrors may
  be because the network is too busy or the
  download site not working. Try another mirror, or
  try again later.
• If setup behaved strangely, check the files
  setup.log' and setup.log.full' in /var/log
  (C\cygwin\var\log by default) to get some clues
  as to what went wrong and why.
• If you're still baffled, email us
  appssupport_at_engr.uconn.edu

22
Create Startxwin Shortcut

• Open C/cygwin (the Cygwin installation root
  folder), and go to the /usr/X11R6/bin folder.
• Right-click on "startxwin" (it might appear as
  "startxwin.bat). Select "Create Shortcut", and
  drag the resulting icon to your Desktop/someplace
  else convenient.

23
Start Cygwin/X

• To start the Cygwin/X server, (double-click the
  startxwin shortcut that you created. After a few
  seconds, the "X" icon appears in the system tray
  and an Xterm window opens.
• This Xterm window starts with a local shell on
  your Windows machine. To run programs on a remote
  host, such as sgi1, you must first log into that
  host.

24
Access Remote Host

• SSH Client Putty SFTP Client WinSCP Other
  SSH Clients
• OpenSSH- double click Cygwin shortcut.
• Log into the remote host ssh -X
  username_at_machine_name
• Type in your password.

25
Shut Down Cygwin/X

• To shut down the Cygwin/X server, right-click on
  the "X" icon in the system tray and click "Exit".

26
Start an X Application

• Start the Cygwin/X server.
• Log into sgi1.engr.uconn.edu either by using
  Putty (make sure to enable X11 forwarding in
  Puttys configuration) or OpenSSH via Cygwin.
• Now you can run programs such as nedit, xclock,
  etc.

27
Uninstall Individual Packages

• Run Cygwin Setup (setup.exe) as you would to
  install packages.
• In the list of packages to install, click on the
  "View" button to get a full listing. Click on
  the cycle glyph until the action reads
  "Uninstall".
• Click "Next to uninstall the selected package.

28
Uninstall All of Cygwin

• Delete the Cygwin root folder and all subfolders
• Delete the Cygwin shortcuts on the Desktop and
  Start Menu, and anything left by setup.exe in the
  download directory.
• Finally, delete the registry tree
  Software\Cygnus Solutions' under
  HKEY_LOCAL_MACHINE and/or HKEY_CURRENT_USER.

29
Uninstall All of Cygwin
30
Uninstall All of Cygwin
31
Cygwin Documentation

• There are quite a lot of document
  http//cygwin.com/docs.html
• A comprehensive Cygwin User's Guide
  http//cygwin.com/cygwin-ug-net/cygwin-ug-net.html
  
• The documentation for the individual GNU tools
  http//www.gnu.org/manual