awesome-copilot/skills/batch-files/references/cygwin.md

Cygwin Reference

Cygwin provides a large collection of GNU and Open Source tools that provide functionality similar to a Linux distribution on Windows, plus a POSIX API DLL (cygwin1.dll) for substantial Linux API compatibility.

Documentation

• Cygwin User's Guide — comprehensive official documentation
• Cygwin FAQ
• Cygwin Homepage

User's Guide — Table of Contents

Chapter 1: Cygwin Overview

• What is it? — POSIX compatibility layer and GNU toolset for Windows
• Quick Start Guide (Windows users) — Getting started for those familiar with Windows
• Quick Start Guide (UNIX users) — Getting started for those familiar with UNIX/Linux
• Are the Cygwin tools free software? — Licensing (GPL/LGPL)
• A brief history of the Cygwin project — Origins and evolution
• Highlights of Cygwin Functionality
  • Permissions and Security
  • File Access
  • Text Mode vs. Binary Mode
  • ANSI C Library
  • Process Creation
  • Signals
  • Sockets and Select
• What's new and what changed — Release notes for all versions (1.7.x through 3.6)

Chapter 2: Setting Up Cygwin

• Internet Setup — Installing via setup-x86_64.exe, mirror selection, package management
• Environment Variables — Configuring PATH, HOME, CYGWIN and other environment variables
• Changing Cygwin's Maximum Memory — Adjusting memory limits via the registry
• Internationalization — Locale and character set configuration
• Customizing bash — .bashrc, .bash_profile, and prompt customization

Chapter 3: Using Cygwin

• Mapping path names — How Cygwin maps POSIX paths to Windows paths (/cygdrive/c = C:\)
• Text and Binary modes — Line ending handling (\n vs \r\n), mount options
• File permissions — POSIX permission model on NTFS, ACLs
• Special filenames — Device files, /proc, /dev, socket files
• POSIX accounts, permission, and security — User/group mapping, passwd/group files, ntsec
• Cygserver — Background service for shared memory, message queues, semaphores
• Cygwin Utilities — Built-in command-line tools:
  • cygcheck — System information and package diagnostics
  • cygpath — Convert between POSIX and Windows paths
  • cygstart — Open files/URLs with associated Windows applications
  • dumper — Create Windows minidumps
  • getconf — Query POSIX system configuration
  • getfacl / setfacl — Get/set file access control lists
  • ldd — List shared library dependencies
  • locale — Display locale information
  • minidumper — Write a minidump of a running process
  • mkgroup / mkpasswd — Generate group/passwd entries from Windows accounts
  • mount / umount — Manage Cygwin mount table
  • passwd — Change passwords
  • pldd — List loaded DLLs for a process
  • profiler — Profile Cygwin programs
  • ps — List running processes
  • regtool — Access the Windows registry from the shell
  • setmetamode — Control meta key behavior in the console
  • ssp — Single-step profiler
  • strace — Trace system calls and signals
  • tzset — Print POSIX-compatible timezone string
• Case-sensitive directories — Enabling per-directory case sensitivity on Windows 10+
• Using Cygwin effectively with Windows — Integration tips, running Windows programs from Cygwin

Chapter 4: Programming with Cygwin

• Using GCC with Cygwin — Compiling C/C++ programs with the Cygwin GCC toolchain
• Debugging Cygwin Programs — Using GDB and other debugging tools
• Building and Using DLLs — Creating shared libraries under Cygwin
• Defining Windows Resources — Resource files and windres
• Profiling Cygwin Programs — Performance profiling with gprof and ssp

Key Concepts for Batch Scripting

Invoking Cygwin from Batch Files

REM Run a Cygwin command from a batch file
C:\cygwin64\bin\bash.exe -l -c "ls -la /home"

REM Convert a Windows path to POSIX for Cygwin
C:\cygwin64\bin\cygpath.exe -u "C:\Users\John Doe\Documents"

REM Convert a POSIX path back to Windows
C:\cygwin64\bin\cygpath.exe -w "/home/jdoe/project"

Common Environment Variables

Variable	Purpose
CYGWIN	Runtime options (e.g., nodosfilewarning, winsymlinks:nativestrict)
HOME	User home directory
PATH	Must include /usr/local/bin:/usr/bin for Cygwin tools
SHELL	Default shell (typically /bin/bash)
TERM	Terminal type for console applications