The Windows Subsystem for Linux lets developers run a GNU/Linux environment – including most command-line tools, utilities, and applications – directly on Windows, unmodified, without the overhead of a traditional virtual machine or dualboot setup.
Windows Subsystem for Linux (WSL) is a feature of Microsoft Windows that allows for using a Linux environment without the need for a separate virtual machine or dual booting. WSL is installed by default in Windows 11. In Windows 10, it can be installed either by joining the Windows Insider program or manually via Microsoft Store or Winget.
The original version, WSL 1, differs significantly from the second major version, WSL 2. WSL 1 (released August 2, 2016), acted as a compatibility layer for running Linux binary executables (in ELF format) by implementing Linux system calls in the Windows kernel. WSL 2 (announced May 2019), introduced a real Linux kernel – a managed virtual machine (via Hyper-V technology) that implements the full Linux kernel. As a result, WSL 2 is compatible with more Linux binaries as not all system calls were implemented in WSL 1.
Microsoft offers WSL for a variety of reasons. Microsoft envisions WSL as "a tool for developers – especially web developers and those who work on or with open source projects". Microsoft also claims that "WSL requires fewer resources (CPU, memory, and storage) than a full virtual machine" (a common alternative for using Linux in Windows), while also allowing the use of both Windows and Linux tools on the same set of files.