apt-cyg - Apt-get like package manager for Cygwin

apt-cyg lets Windows users install and manage Cygwin packages from a command-line session using apt-get-like commands. It operates inside an existing Cygwin installation, cooperating with Cygwin Setup and its repository rather than acting as a separate Windows package system. Its familiar command structure suits developers, administrators, and other Cygwin users who prefer shell-based package work.

The script can be made executable and optionally placed in a bin directory on the command path. Its dist-upgrade operation uses setup-x86.exe or setup-x86_64.exe as a backend, but terminates all running Cygwin tasks before the upgrade starts. It recognizes md5, sha1, sha224, sha256, and sha512 hashes, allowing it to work with both Cygwin and Cygwinports repositories despite their differing verification algorithms. GnuPG signature checking for setup.ini is enabled by default; users can bypass it with the no-verify or -X options, use the embedded trusted keys for Cygwin and Cygwinports, or manage other keys through key-* subcommands.

Using apt-cyg requires the Cygwin default environment plus wget, ca-certificates, gnupg, and libiconv. On 32-bit Cygwin, wget also needs an additional ca-certificates setting, while 64-bit Cygwin does not require that wget adjustment; certificate setup has a known problem on x86_64 Cygwin with Windows 8. A copy tracked by Git can update itself through upgrade-self, and the --proxy or -p option accepts auto or inherit. Published by kou1okada, apt-cyg is freeware in the System Tools category for Windows, with version 2025.9.3.