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Cygwin

cygwin.com

Free plan Windows
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Spec score 7.7 #6 of 26 in Windows Compatibility Layers

What it is

Cygwin supplies GNU and other open-source tools on Windows through a library implementing POSIX system calls and environment behavior. Its distribution contains thousands of packages, including GNU and BSD tools, an X server, and X applications. Developers can use its tools, headers, and libraries to build Windows console or GUI programs with parts of the POSIX API or to port Unix software. Programs can run from shells such as bash, tcsh, and zsh. The recommended Cygwin Setup GUI lets users select packages and update them separately; only a minimal base set, about 100 MB, is installed by default. Command-line options support automated setup, and a local repository can support offline installation. Setup verifies signed metadata and downloaded-package hashes. The current DLL supports recent 64-bit Windows versions from Windows 8.1, with documented x64 emulation on Windows 11 ARM PCs. Cygwin is free, but native Linux applications must be rebuilt from source.

Spec sheet

What it does
Cygwin provides GNU and other open source tools on Windows, with a library that supplies POSIX system calls and environment.Read 9 Oct 2026 · cygwin.com
Security
Setup verifies signed package metadata and checks downloaded packages against their listed cryptographic hashes; the FAQ says Cygwin uses SHA-512 for setup metadata.Read 9 Oct 2026 · cygwin.com
Support
The project directs users to its FAQ, User's Guide, mailing list archives, and mailing lists for questions and bug reports.Read 9 Oct 2026 · cygwin.com
Automation and offline use
Setup accepts command-line arguments for automated installs, and the site documents installing from a local package repository without internet access.Read 9 Oct 2026 · cygwin.com
For developers
Cygwin includes tools, headers, and libraries for writing Windows console or GUI applications using parts of the POSIX API and for porting Unix programs.Read 9 Oct 2026 · cygwin.com
Included software
The distribution includes thousands of packages, including GNU and BSD tools, an X server, and X applications.Read 9 Oct 2026 · cygwin.com
Installation
The recommended installation method is the Cygwin Setup GUI, which lets users choose packages and update them individually.Read 9 Oct 2026 · cygwin.com
Licensing
Cygwin tools use various licenses, including GPL, public domain, and X11-style licenses; the Cygwin API library is under LGPL version 3 or later.Read 9 Oct 2026 · cygwin.com
Not supported
Cygwin does not run native Linux applications on Windows; applications must be rebuilt from source to run with Cygwin.Read 9 Oct 2026 · cygwin.com
Package selection
Only minimal base packages are installed by default, taking about 100 MB, and users can select additional packages in Setup.Read 9 Oct 2026 · cygwin.com
Package updates
Individual packages are released separately from the Cygwin DLL, so the DLL version is not a general distribution release number.Read 9 Oct 2026 · cygwin.com
Shells
Cygwin programs can be used from shells including bash, tcsh, and zsh.Read 9 Oct 2026 · cygwin.com
Supported platform
The current Cygwin DLL supports recent 64-bit Windows versions starting with Windows 8.1; the FAQ also describes x64 emulation on ARM PCs running Windows 11.Read 9 Oct 2026 · cygwin.com

Plans and prices

Cygwin Free Free to use; source and binaries are free to download. Windows only · installable packages selected individually · does not run native Linux apps without rebuilding from source Read 9 Oct 2026 · cygwin.com

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Strong points and limits

Strong points

  • Thousands of GNU and BSD packages
  • Includes bash, tcsh, and zsh shells
  • Supports automated and offline setup
  • Provides POSIX development libraries
  • Free to download and use

Limits

  • Windows only
  • Native Linux applications require rebuilding
  • Minimal installation needs additional package selection
  • Packages update separately from the DLL

Who it suits

It suits Windows developers and users who need Unix-style tools, shells, or POSIX-oriented development. It is also useful for controlled package selection and offline installation.

Verdict

Cygwin offers a broad Unix-like toolkit and POSIX development layer on Windows. Its package-based installation is flexible, but it is not a runtime for unmodified Linux applications.

Where Specifiction places it

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