CS2030 AY19/20 Semester 2
Peer Learning
  • Introduction
  • Textbook Contributions
  • Peer Learning Tasks
  • Piazza Participation
    •
    Guides
  • Setting Up Lab Environment
  • Setting Up Java
  • Setting Up Vim
  • Setting Up MacVim
  • Setting Up Sunfire and PE Nodes
  • Setting Up Checkstyle
    •
  • Textbook
    • Links
  • CS2030 Java Style Guide
  • CS2030 Javadoc Specification
  • JDK 11 Download Link
  • Codecrunch
  • Github Repo
  • Piazza Forum
    •

    • Accessing files in WSL


    Edit the material here!

    If you are NOT a Windows user, you can safely ignore this section.

    If you are using Windows for CS2030, chances are you are using Windows Subsystem for Linux. You might be wondering: where do you find your files? Where should you keep your files?

    First of all, we need to understand that WSL is a completely different system from Windows. Windows is based on (for argument's sake, due to the long history of Windows), the Windows NT kernel, while Linux is based on, well, Linux kernel. Let's just say Linux is Unix-like.

    As such, the ways they manage their files (filesystem) are very different as well. Windows prefers NTFS (the Windows NT File System), while Linux prefers ext4 or other filesystems.

    These filesystems affect the properties of a file/folder, called metadata. They are managed by filesystems, and contain information such as date modified, date created, or permissions. The latter is bold because that is the most important aspect in a file's metadata.

    One can imagine that modifying Linux files in Windows may result in Windows not meeting the metadata requirements of Linux's filesystem, such that when the file/folder is accessed with WSL (Linux), errors such as file lock, insufficient permissions, or even corruption may occur.

    Therefore, even though one knows that the home (or, tilde ~) directory for WSL is located at

    C:\Users\%USERNAME%\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc\LocalState\rootfs\home

    this directory shall never be touched or accessed through Windows' File Explorer as Windows may unintentionally replace the metadata of whatever related to that directory, causing problems later in WSL. An experienced WSL user always knows this.

    Now, you may ask, how do we access our files then? There are two ways to access WSL files safely and correctly, as advised by Microsoft:

    1. Accessing the root filesystem / directory with \\wsl$\<DistroName>\ (e.g. \\wsl$\Ubuntu\ for Ubuntu users, \\wsl$\Kali\ users, etc). This will create a specialised P9 fileserver, which will expose the Linux file system as a local network directory in Windows. Whatever you do there will be properly adjusted by the magic of Windows x WSL.

    2. Accessing the Linux directory by invoking explorer.exe . (yes, the last . there is NOT a typo) in WSL. This will open up a File Explorer window and redirect you to your current working directory. The directory opened is also a form of the aforementioned P9 fileserver.

    If the problems caused by accessing the Linux files through AppData is just a permissions mismatch, one can fix by using chmod. But, if the problem is file corruption, there might not be a way back. Therefore, this section intends to disseminate the correct way of accessing files in WSL. I hope you will become one of the informed ones.

    You can read more about this issue in this Microsoft DevBlogs article.