Using Cygwin
============

How should I set my PATH?
-------------------------

If you look at the "Cygwin 1.1.0" (or similar) shortcut created in the "Cygnus Solutions" programs folder, you'll see that it runs C:\cygwin\bin\cygwin.bat (assuming your root is C:\cygwin).  The contents should look something like this:

     	@echo off
     	SET MAKE_MODE=unix
     	SET PATH=C:\cygwin\bin;C:\cygwin\usr\local\bin;%PATH%
     	bash

Effectively, this prepends /usr/bin and /usr/local/bin to your Windows system path.  If you choose to reset your PATH, say in $HOME/.bashrc, then you should follow this rule.  You must have /usr/bin in your PATH before any Windows system directories.  (And you must not omit the Windows system directories!) Otherwise you will likely encounter all sorts of problems running Cygwin applications.

If you haven't messed up the default mounts, then /bin and /usr/bin are the same location, so you only need one of them in your PATH.  You should use /usr/local/bin for installing additional Cygwin applications that are not part of the core net release.  (That is, anything not found in an ftp mirror of latest and installed by setup.exe.)

How do I convert between Windows and UNIX paths?
------------------------------------------------

Use the 'cygpath' utility.  Type 'cygpath' with no arguments to get usage information.  For example (on my installation):

     	bash$ cygpath --windows ~/.bashrc
             D:\starksb\.bashrc
             bash$ cygpath --unix C:/cygwin/bin/cygwin.bat
             /usr/bin/cygwin.bat
             bash$ cygpath --unix C:\\cygwin\\bin\\cygwin.bat
             /usr/bin/cygwin.bat

Note that bash interprets the backslash '\' as an escape character, so you must type it twice in the bash shell if you want it to be recognised as such.

Why doesn't bash read my .bashrc file on startup?
-------------------------------------------------

Your .bashrc is read from your home directory specified by the HOME environment variable.  It uses /.bashrc if HOME is not set.  So you need to set HOME correctly, or move your .bashrc to the top of the drive mounted as / in Cygwin.

How can I get bash filename completion to be case insensitive?
--------------------------------------------------------------

"shopt -s nocaseglob" should do the trick.

Can I use paths/filenames containing spaces in them?
----------------------------------------------------

Cygwin does support spaces in filenames and paths.  That said, some utilities that use the library may not, since files don't typically contain spaces in Unix.  If you stumble into problems with this, you will need to either fix the utilities or stop using spaces in filenames used by Cygwin tools.

In particular, bash interprets space as a word separator.  You would have to quote a filename containing spaces, or escape the space character. For example:

     	bash-2.03$ cd '/cygdrive/c/Program Files'

or

     	bash-2.03$ cd /cygdrive/c/Program\ Files

Why can't I cd into a shortcut to a directory?
----------------------------------------------

Cygwin does not follow MS Windows Explorer Shortcuts (*.lnk files).  It sees a shortcut as a regular file and this you cannot "cd" into it.

Some people have suggested replacing the current symbolic link scheme with shortcuts.  The major problem with this is that .LNK files would then be used to symlink Cygwin paths that may or may not be valid under native Win32 non-Cygwin applications such as Explorer.

I'm having basic problems with find. Why?
-----------------------------------------

Make sure you are using the find that came with Cygwin and that you aren't picking up the Win32 find command instead.  You can verify that you are getting the right one by doing a "type find" in bash.

Why doesn't man work?
---------------------

Even after installing the man package, you get an error like this:

     	bash-2.03$ man man
     	Error executing formatting or display command.
     	System command (cd /usr/man ; (echo -e ".pl 1100i"; cat /usr/man/man1/man.1; echo ".pl \n(nlu+10") | /usr/bin/tbl | /usr/bin/groff -Tascii -mandoc | less -is) exited with status 32512.
     	No manual entry for man

You also need /bin/sh, which is found in the ash package. Install this too.

Why doesn't chmod work?
-----------------------

ntsec will allow UNIX permissions in Windows NT on NTFS file systems.

ntea works on NTFS and FAT but it creates a huge, undeletable file on FAT filesystems.

There is no solution at all for Windows 9x.

These are settings for the CYGWIN environment variable.  See the Cygwin User's Guide at http://sources.redhat.com/cygwin/cygwin-ug-net/cygwin-ug-net.html for more information on this variable and its settings.

Why doesn't mkdir -p work on a network share?
---------------------------------------------

Unfortunately, you cannot do something like this:

     bash$ mkdir -p //MACHINE/Share/path/to/new/dir
     mkdir: cannot create directory `//MACHINE': No such file or directory

This is because mkdir checks for the existence of each directory on the path, creating them as necessary.  Since //MACHINE is not a directory (you can't cd to it either), mkdir tries to create it, and fails.

This might get fixed someday, but for now, you have to work around it:

     bash$ cd //MACHINE/Share
     bash$ mkdir -p path/to/new/dir

Why doesn't my script work?
---------------------------

There are two basic problems you might run into.  One is the fact that /bin/sh is really ash, and is missing some features you might expect in /bin/sh.  For example:

  bullet No job control

  bullet No getopts

  bullet No functions exported

Or it could be a permission problem, and Cygwin doesn't understand that your script is executable.  Because chmod may not work (see FAQ entry above), Cygwin must read the contents of files to determine if they are executable.  If your script does not start with

     	#! /bin/sh

(or any path to a script interpreter, it does not have to be /bin/sh) then Cygwin will not know it is an executable script.  The Bourne shell idiom

     	:
     	# This is the 2nd line, assume processing by /bin/sh

also works.

Note that you can use mount -x to force Cygwin to treat all files under the mount point as executable.  This can be used for individual files as well as directories.  Then Cygwin will not bother to read files to determine whether they are executable.

Why don't cursor keys work under Win95/Win98?
---------------------------------------------

(Please note: This section has not yet been updated for the latest net release.)

Careful examination shows that they not just non-functional, but rather behave strangely, for example, with NumLock off, keys on numeric keyboard work, until you press usual cursor keys, when even numeric stop working, but they start working again after hitting alphanumeric key, etc. This reported to happen on localized versions of Win98 and Win95, and not specific to Cygwin (there're known cases of Alt+Enter (fullscreen/windowed toggle) not working and shifts sticking with other programs). The cause of this problem is Microsoft keyboard localizer which by default installed in 'autoexec.bat'. Corresponding line looks like:

     keyb ru,,C:\WINDOWS\COMMAND\keybrd3.sys

(That's for russian locale.) You should comment that line if you want your keys working properly. Of course, this will deprive you of your local alphabet keyboard support, so you should think about another localizer. exUSSR users are of course knowledgable of Keyrus localizer, and it might work for other locales too, since it has keyboard layout editor. But it has russian messages and documentation ;-( Reference URL is http://www.hnet.ru/software/contrib/Utils/KeyRus/ (note the you may need to turn off Windows logo for Keyrus to operate properly).

Is it OK to have multiple copies of the DLL?
--------------------------------------------

You should only have one copy of the Cygwin DLL on your system.  If you have multiple versions, they will conflict and cause problems.

If you get the error "shared region is corrupted" it means you have multiple versions of cygwin1.dll running at the same time.  This could happen, for example, if you update cygwin1.dll without exiting all Cygwin apps (including inetd) beforehand.

Where can I find "more"?
------------------------

If you are looking for the "more" pager, you should use the "less" pager instead.

Where can I find "which"?
-------------------------

There is no "which" command with Cygwin.  However, you can use the bash shell builtin "type" which does something similar.

How can I access other drives?
------------------------------

You have some flexibility here.

Cygwin has a builtin "cygdrive prefix" for drives that are not mounted. You can access any drive, say Z:, as '/cygdrive/z/'.

In some applications (notably bash), you can use the familiar windows <drive>:/path/, using posix forward-slashes ('/') instead of Windows backward-slashes ('\').  (But see the warning below!)  This maps in the obvious way to the Windows path, but will be converted internally to use the Cygwin path, following mounts (default or explicit).  For example:

     	bash$ cd C:/Windows
     	bash$ pwd
             /cygdrive/c/Windows

and

     	bash$ cd C:/cygwin
     	bash$ pwd
             /

for a default setup.  You could also use backward-slashes in the Windows path, but these would have to be escaped from the shell.

Warning: There is some ambiguity in going from a Windows path to the posix path, because different posix paths, through different mount points, could map to the same Windows directory.  This matters because different mount points may be binmode or textmode, so the behaviour of Cygwin apps will vary depending on the posix path used to get there.

You can avoid the ambiguity of Windows paths, and avoid typing "/cygdrive", by explicitly mounting drives to posix paths.  For example:

     	bash$ mkdir /c
     	bash$ mount c:/ /c
     	bash$ ls /c

Then /cygdrive/c/Windows becomes /c/Windows which is a little less typing.

Note that you only need to mount drives once.  The mapping is kept in the registry so mounts stay valid pretty much indefinitely. You can only get rid of them with umount, or the registry editor.

The '-b' option to mount mounts the mountpoint in binary mode ("binmode") where text and binary files are treated equivalently.  This should only be necessary for badly ported Unix programs where binary flags are missing from open calls.  It is also the setting for /, /usr/bin and /usr/lib in a default Cygwin installation.  The default for new mounts is text mode ("textmode"), which is also the mode for all "cygdrive" mounts.

You can change the default cygdrive prefix and whether it is binmode or textmode using the mount command.  For example,

     	bash$ mount -b --change-cygdrive-prefix cygdrive

will change all /cygdrive/... mounts to binmode.

How can I copy and paste into Cygwin console windows?
-----------------------------------------------------

Under Windows NT, open the properties dialog of the console window. The options contain a toggle button, named "Quick edit mode".  It must be ON.  Save the properties.

Under Windows 9x, open the properties dialog of the console window. Select the Misc tab.  Uncheck Fast Pasting.  Check QuickEdit.

What does "mount failed: Device or resource busy" mean?
-------------------------------------------------------

(Please note: This section has not yet been updated for the latest net release.)

This usually means that you are trying to mount to a location already in use by mount.  For example, if c: is mounted as '/' and you try to mount d: there as well, you will get this error message.  First "umount" the old location, then "mount" the new one and you should have better luck.

If you are trying to umount '/' and are getting this message, you may need to run regedit.exe and change the "native" key for the '/' mount in one of the mount points kept under HKEY_CURRENT_USER/Software/Cygnus Solutions/CYGWIN.DLL setup/<version> where <version> is the latest registry version associated with the Cygwin library.

How can I share files between Unix and Windows?
-----------------------------------------------

During development, we have both Unix boxes running Samba and NT/Windows 95/98 machines.  We often build with cross-compilers under Unix and copy binaries and source to the Windows system or just toy with them directly off the Samba-mounted partition. On dual-boot NT/Windows 9x machines, we usually use the FAT filesystem so we can also access the files under Windows 9x.

Are mixed-case filenames possible with Cygwin?
----------------------------------------------

Several Unix programs expect to be able to use to filenames spelled the same way, but with different case.  A prime example of this is perl's configuration script, which wants Makefile and makefile.  WIN32 can't tell the difference between files with just different case, so the configuration fails.

In releases prior to beta 16, mount had a special mixed case option which renamed files in such a way as to allow mixed case filenames.  We chose to remove the support when we rewrote the path handling code for beta 16.  The standard Windows apps -- explorer.exe, cmd.exe/command.com, etc. -- do not distinguish filenames that differed only in case, resulting in some (very) undesirable behavior.

Sergey Okhapkin had maintained a mixed-case patch ('coolview') until about B20.1, but this has not been updated to recent versions of Cygwin.

What about DOS special filenames?
---------------------------------

Files cannot be named com1, lpt1, or aux (to name a few); either as the root filename or as the extension part.  If you do, you'll have trouble.  Unix programs don't avoid these names which can make things interesting.  E.g., the perl distribution has a file called aux.sh.  The perl configuration tries to make sure that aux.sh is there, but an operation on a file with the magic letters 'aux' in it will hang.

When it hangs, how do I get it back?
------------------------------------

If something goes wrong and the tools hang on you for some reason (easy to do if you try and read a file called aux.sh), first try hitting ^C to return to bash or the cmd prompt.

If you start up another shell, and applications don't run, it's a good bet that the hung process is still running somewhere.  Use the Task Manager, pview, or a similar utility to kill the process.

And, if all else fails, there's always the reset button/power switch. This should never be necessary under Windows NT.

Why the weird directory structure?
----------------------------------

Why do /lib and /usr/lib (and /bin, /usr/bin) point to the same thing?

Why use mounts instead of symbolic links?

Can I use a disk root (e.g., C:\) as Cygwin root?  Why is this discouraged?

After a new installation in the default location, your mount points will look something like this:

     Device              Directory           Type         Flags
     C:\cygwin\bin       /usr/bin            user         binmode
     C:\cygwin\lib       /usr/lib            user         binmode
     C:\cygwin           /                   user         binmode

Note that /bin and /usr/bin point to the same location, as do /lib and /usr/lib.  This is intentional, and you should not undo these mounts unless you really know what you are doing.

Various applications and packages may expect to be installed in /lib or /usr/lib (similarly /bin or /usr/bin).  Rather than distinguish between them and try to keep track of them (possibly requiring the occasional duplication or symbolic link), it was decided to maintain only one actual directory, with equivalent ways to access it.

Symbolic links had been considered for this purpose, but were dismissed because they do not always work on Samba drives.  Also, mounts are faster to process because no disk access is required to resolve them.

Note that non-cygwin applications will not observe Cygwin mounts (or symlinks for that matter).  For example, if you use WinZip to unpack the tar distribution of a Cygwin package, it may not get installed to the correct Cygwin path.  So don't do this!

It is strongly recommended not to make the Cygwin root directory the same as your drive's root directory, unless you know what you are doing and are prepared to deal with the consequences.  It is generally easier to maintain the Cygwin hierarchy if it is isolated from, say, C:\.  For one thing, you avoid possible collisions with other (non-cygwin) applications that may create (for example) \bin and \lib directories. (Maybe you have nothing like that installed now, but who knows about things you might add in the future?)

How do anti-virus programs like Cygwin?
---------------------------------------

Users have reported that NAI (formerly McAfee) VirusScan for NT (and others?) is incompatible with Cygwin.  This is because it tries to scan the newly loaded shared memory in cygwin1.dll, which can cause fork() to fail, wreaking havoc on many of the tools.  (It is not confirmed that this is still a problem, however.)

There have been several reports of NAI VirusScan causing the system to hang when unpacking tar.gz archives.  This is surely a bug in VirusScan, and should be reported to NAI.  The only workaround is to disable VirusScan when accessing these files.  This can be an issue during setup, and is discussed in that FAQ entry.

Some users report a significant performance hit using Cygwin when their anti-virus software is enabled.  Rather than disable the anti-virus software completely, it may be possible to specify directories whose contents are exempt from scanning.  In a default installation, this would be C:\cygwin\bin.  Obviously, this could be exploited by a hostile non-Cygwin program, so do this at your own risk.

Why can't I run bash as a shell under NT Emacs?
-----------------------------------------------

The Windows port of GNU Emacs (aka "NT emacs") uses the Windows command shell by default.  Also, since Emacs is not a Cygwin application, it has no knowledge of Cygwin mounts.  With those points in mind, you need to add the following code to your ~/.emacs or ~/_emacs file in order to use bash.  This is particularly useful for the JDE package (http://sunsite.dk/jde/).

     	;; This assumes that Cygwin is installed in C:\cygwin (the
     	;; default) and that C:\cygwin\bin is not already in your
     	;; Windows Path (it generally should not be).
     	;;
     	(setq exec-path (cons "C:/cygwin/bin" exec-path))
     	(setenv "PATH" (concat "C:\\cygwin\\bin;" (getenv "PATH")))
     	;;
     	;; NT-emacs assumes a Windows command shell, which you change
     	;; here.
     	;;
     	(setq process-coding-system-alist '(("bash" . undecided-unix)))
     	(setq w32-quote-process-args ?\")
     	(setq shell-file-name "bash")
     	(setenv "SHELL" shell-file-name)
     	(setq explicit-shell-file-name shell-file-name)
     	;;
     	;; This removes unsightly ^M characters that would otherwise
     	;; appear in the output of java applications.
     	;;
     	(add-hook 'comint-output-filter-functions
     	          'comint-strip-ctrl-m)

info error "dir: No such file or directory"
-------------------------------------------

Cygwin packages install their info documentation in the /usr/info directory.  But you need to create a dir file there before the standalone info program (probably /usr/bin/info) can be used to read those info files.  This is how you do it:

     	bash$ cd /usr/info
     	bash$ for f in *.info ; do install-info $f dir ; done

This may generate warnings:

     	install-info: warning: no info dir entry in `gzip.info'
     	install-info: warning: no info dir entry in `time.info'

The install-info command cannot parse these files, so you will have to add their entries to /usr/info/dir by hand.

Why do I get a message saying Out of Queue slots?
-------------------------------------------------

(Please note: This section has not yet been updated for the latest net release.)

"Out of queue slots!" generally occurs when you're trying to remove many files that you do not have permission to remove (either because you don't have permission, they are opened exclusively, etc).  What happens is Cygwin queues up these files with the supposition that it will be possible to delete these files in the future.  Assuming that the permission of an affected file does change later on, the file will be deleted as requested.  However, if too many requests come in to delete inaccessible files, the queue overflows and you get the message you're asking about.  Usually you can remedy this with a quick chmod, close of a file, or other such thing.  (Thanks to Larry Hall for this explanation).

Why don't symlinks work on samba-mounted filesystems?
-----------------------------------------------------

Symlinks are marked with "system" file attribute.  Samba does not enable this attribute by default.  To enable it, consult your Samba documentation and then add these lines to your samba configuration file:

     	map system = yes
     	create mask = 0775

Note that the 0775 can be anything as long as the 0010 bit is set.

Why does df report sizes incorrectly.
-------------------------------------

(Please note: This section has not yet been updated for the latest net release.)

There is a bug in the Win32 API function GetFreeDiskSpace that makes it return incorrect values for disks larger than 2 GB in size. Perhaps that may be your problem?

Has the screen program been ported yet?
---------------------------------------

(Please note: This section has not yet been updated for the latest net release.)

Screen requires either unix domain sockets or fifoes.  Neither of them have been implemented in Cygwin yet.