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Written by Oleksandr Gavenko (AKA gavenkoa), compiled on 2017-10-13 from rev 5ee52f8d25b5.



Run setup.exe. Use output dir like:


Add to your PATH env var exactly before C:WINDOWSsystem32;C:WINDOWS values:

set PATH=d:\opt\cygwin\bin;d:\opt\cygwin\usr\local\bin;%PATH%

REM Set CYGWIN variable to 'nontsec'. That makes sure that permissions
REM on your windows machine are not updated as a side effect of cygwin
REM operations.
set CYGWIN=binary nontsec nodosfilewarning codepage:cp1251 noglob

set LANG=ru_RU.cp1251

Set HOME env var (where places config file and projects):

set HOME=d:\home

Set TMP and TEMP env vars with good path (without spaces, etc.; these vars already set as used defined, so you need change their values):

set TMP=c:\tmp
set TEMP=c:\tmp

Also you need edit /etc/passwd to point to correct home path.

Starting from Cygwin /etc/nsswitch.conf settings used to define user home. By default it is /home/%U so it is better to create symlink:

$ ln -s /cygdrive/d/home /home/user

Alternatively with native Windows symlink (from build-in cmd command):

cmd# mklink /D c:\opt\cygwin\home\user c:\home

List of installed packages (-c - check, -d - dump only):

$ cygcheck -c -d

Alternatively look to file content:

How can I change my Cygwin home folder after installation?


Cygwin C API man pages and user guide manuals available in cygwin-doc package.

Documentation unpacked to /usr/share/doc/cygwin-... directory.

apt-cyg package manager

apt-cyg is based on bash, wget, tar, gawk and bzip2 packages and provide convenient commands for managing and queries packages:

$ apt-cyg update
$ apt-cyg install emacs-w32
$ apt-cyg remove emacs-w32

Information about package and dependencies:

$ apt-cyg show emacs-w32
$ apt-cyg depends wget
$ apt-cyg rdepends emacs

List installed packages:

$ apt-cyg list

Search for package with file across installed packages:

$ apt-cyg search stdio.h

List package files for installed packages:

$ apt-cyg listfiles util-linux

Search for package with file through cygwin.com:

$ apt-cyg searchall stdio.h

List all packages in setup.ini:

$ apt-cyg listall

Find package by regex:

$ apt-cyg listall ^emacs

To switch between mirrors:

$ apt-cyg mirror ftp://ftp.cygwinports.org/pub/cygwinports
$ apt-cyg update
$ apt-cyg install php

$ apt-cyg mirror ftp://www.fruitbat.org/pub/cygwin/circa/2016/08/30/104223

$ apt-cyg mirror http://mirrors.kernel.org/sources.redhat.com/cygwin/

Just switching mirror does not update metadata.

To change a location of directory where packages and setup.ini downloaded:

$ apt-cyg cache

$ apt-cyg cache ~/net
Cache set to C:\home\net.
Home page.
Request to support multiply sources.
How to add a repository using apt-cyg.
Depricated way to install from several sources with -m option using shell aliases as a trick.

Cygwin file permission

Get list of permissions:

$ getfacl .

rsync without problems:

$ rsync -ar —chmod=ugo=rwX $FROM/ $TO/
File permissions.
POSIX accounts, permission, and security.
Cygwin sets file permission to 000.

Installation on Windows XP

Cygwin from v2.5.5 and Setup version 2.874 (on 25 Aug 2016) is latest version with Windows XP support. Later versions build with dependencies on newer syscalls and failt to run in Windows XP.

Latest mirrors avaialble at fruitbat.org:

To run setup against this mirror:

cmd> setup.exe

setup.exe available at:

Run as (-X disable signature verification, -s <url> option select a particular mirror, -O option disallow any other mirrors):

cmd> setup-x86.exe -X -s ftp://www.fruitbat.org/pub/cygwin/circa/2016/08/30/104223 -O
Description of Cygwin time machine project.
Question about Cygwin old mirror.
Question about Cygwin old mirror.
Another old mirror.

Cygwin ports

This project provides Cygwin binary and source packages for a large variety of programs and libraries, including the GNOME and KDE desktop environments

Newest home of the Cygwin Ports project.
Home page.
Official blog.
cygport scripts to compile cygwinports
Source packaging tool for Cygwin
Cygport Reference Manual.

Which Cygwin version you run?

$ uname -r
$ cygcheck -c cygwin
Cygwin Package Information
Package              Version        Status
cygwin               1.7.7-1        OK

Rebase dll

In order to Cygwin to maintain fork() syscall it should preserve same logical base address for dll to be able to share library between child and parent process. It was done via special hints in dlls.

With new version of Cygwin software or external Windows libraries (AntiVirus may inject its their libraries into Cygwin process address space) it may happen that new library is overlapped with existing.

There is rebase utility that changes base address hints for dll.

You should finish all Cygwin processes in order to rebase to succeed.

You may trigger automatic rebase of all packages in next run of setup.exe with:

$ rebase-trigger full

Read more at:

Handling repeated failures of rebaseall to allow cygwin remaps.

Recreate /etc/passwd and /etc/groups.

$ mkpasswd -d | grep $yourlogin > /etc/passwd  # if you in Windows domain
$ mkpasswd -l > /etc/passwd                    # if you in Windows domain

$ mkgroup -l > /etc/group

Adding mount points.


C:/foo /bar/baz ntfs text,posix=0 0 0
/var /usr/var none bind

Running X Window.

$ XWin -multiwindow&


$ XWin -clipboard -silent-dup-error -xkblayout "us,ru" -xkboptions "grp:caps_toggle"&

To start X application you must set 'DISPLAY':

$ DISPLAY=:0 xterm&

Working with packages.

List of package files.

$ cygcheck -l pkg-name

Search packages by containing path (only under installed packages).

$ for f in /etc/setup/*.lst.gz; do gzip -c -d $f | grep $WORD  2>&1 >/dev/null && { echo $f; break; } || :; done

Search for package.

If you have file name or regex use (need internet connection):

$ cygcheck -p REGEX

cygcheck use such link:


Cygwin installation info.

$ uname -a
$ cygcheck -s -r

Cygwin acronyms.

One encounters all sorts of acronyms on the Cygwin mailing lists.

Check dll dependency.

$ ldd my.dll
$ ldd my.exe
$ cygcheck ./my.dll
$ cygcheck ./my.exe

Cygwin alternatives.

Subsystem for Unix-based Applications and Services for Unix