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Windows Subsystem for Linux (WSL), and Ubuntu

Other Windows 10 related notes

What is described on this page was tested with WSL v1, and not WSL 2

WSL 2 is available in Windows 10 v2004 (April 2020) and more recent, and should also be available in 1903 and 1909 versions

The user can choose to install Linux using WSL1 or WSL2. Check the differences between WSL1 and WSL2 before choosing

Read just the top of the Windows Subsystem for Linux Documentation for a quick WSL description on the Microsoft site

In a few words, WSL is not Linux, it's more a way to share files between Windows and Linux (it's OK to skip this rather technical link!). Files under the Linux root (i.e. /) are controlled by WSL which mimics Linux specific behavior [...follow the link for details...]. That's why you need to activate WSL and then install a Linux distribution.


  • A computer running at least Windows 10 Anniversary Update, that is with a version number of 1607 (July 2016) or higher
  • Enough space on C:\. Microsoft instructions say The Windows Subsystem for Linux only runs on your system drive (usually this is your C: drive)
    • Exporting a simple Ubuntu configuration (after doing everything from Base installation to Advanced configuration below) with the wsl --export command generated a 2.7 Gb tar file (uncompressed), so it's probably good to start with at least 3 Gb of free space on C:\ (and you always need to keep enough free space on C:\ for regular Windows operation)
    • The Linux / and /home partitions will always be on C:, but the data files can be on any Windows disk/partition (or external drive) of the computer
      • the Windows partitions will be available and accessible in /mnt/, so you can store data on other partitions (e.g. the content of the Windows D:\ partition will be available in /mnt/d in Linux)
    • The files will be installed in hidden partitions of the current user's directory on C:\: e.g. C:\Users\<your_login>. Other users of the same Windows 10 computer would have to install Ubuntu again, in their own user directory
      • Checking the properties of C:\Users\<your_login> will not report an accurate size and number of files, because lots of files and directories are hidden! On the test laptop, the reported size of the user backed up directory (with SyncBackFree) was ~20 Gb (user data, WSL+Ubuntu, custom install of the CDAT 8.1 python distribution)
      • Be sure to monitor the remaining free space on C:!
  • Note: it seems that wsl --import can restore a backed-up Linux to a user specified location. Maybe this can be used for moving Ubuntu…

Base installation

  • Follow closely the steps listed in WSL Windows 10 Installation Guide. Open this WSL Windows 10 Installation Guide in another window, so that you can read the useful hints below at the same time!
    • When you have to Open PowerShell as Administrator, go to StartWWindows PowerShell then right-clik on Windows PowerShell and select Run as Administrator
    • FIXME At this stage, we could try to restore/clone a previously installed/customized/backed-up version of Ubuntu if we have one (see Restoring a WSL backup)
    • In the Install your Linux Distribution of Choice, we will use the very easy install from the Microsoft Store option
      • Open the Microsoft Store with: StartMicrosoft Store
      • In the Microsoft Store, just search Linux and select the generic Ubuntu (select the Ubuntu that has no version number after the name)
      • Select Get (Télécharger) to download the installer package. You can ignore (No thanks) the popups asking you to use a Microsoft account, if you are not using a Microsoft account yet on this machine
      • Select Launch (Lancer) to start the installation, and give a user name (e.g. your LSCE login) and password (something that you can remember, but maybe not the same password as your LSCE account)
      • Type some basic Linux commands to check that things are working, e.g. check the available disks
        $ df -h
        Filesystem      Size  Used Avail Use% Mounted on
        rootfs          238G   58G  181G  25% /
        none            238G   58G  181G  25% /dev
        none            238G   58G  181G  25% /run
        none            238G   58G  181G  25% /run/lock
        none            238G   58G  181G  25% /run/shm
        none            238G   58G  181G  25% /run/user
        cgroup          238G   58G  181G  25% /sys/fs/cgroup
        C:\             238G   58G  181G  25% /mnt/c
        D:\             932G  8.1G  924G   1% /mnt/d
      • Update your Ubuntu Linux with:

After the base installation

Once you have completed the base installation steps, you'll get a Ubuntu machine, with a root and user account (pre-configured to use sudo for commands that need root access) and lots of pre-installed applications (but no graphics).

Opening a terminal

  • Check the next sections to find out the different ways to open terminals
  • Opening the first terminal will start WSL+Ubuntu
  • Closing all terminals will not stop WSL+Ubuntu. Read the rebooting WSL section if you need a clean start of WSL without rebooting Windows

Having a terminal you can efficiently interact with is the basis of your future work with WSL+Ubuntu! You can optionally read the ConEmu vs Hyper vs Terminus vs MobaXTerm Terminator vs Ubuntu WSL blog if you really want more details

The default terminal

The Default WSL+Ubuntu terminal is basically a bash shell running inside a regular Windows cmd text console. You do not need to have an X server running to use it!

There are several ways to open a default terminal:

  • Select Ubuntu from the Start menu
  • Click on the Ubuntu icon on the task bar
    • if you don't have a Ubuntu icon on the task bar yet: right-click on the Ubuntu icon (in the Start menu) → More → Pin to the task bar
    • to open more terminals: right-click on the Ubuntu icon on the task bar → Ubuntu
  • Type ubuntu+<Enter> or wsl+<Enter> in the (Cortana) Search field on the task bar
Copy/paste in the default terminal

Follow the steps in Copy and Paste arrives for Linux/WSL Consoles and you will then be able to copy/paste by using Shift+Ctrl+C/V

  • The QuickEdit mode should already be selected by default and you can also:
    • select text with the left mouse button
    • paste the selected text with the right mouse button (click twice after a new selection)
  • Use Alt+<Enter> to toggle the terminal to full screen (maybe more useful options here?)

The WSLtty terminal

  • This is the recommended (by JYP) option for now
  • If you can't open a terminal after Windows upgrades from WSL to WSL v2, get and install the latest version of WSLtty !

WSLtty allows you to use the efficient Mintty as a terminal for WSL. You do not need to have an X server running to use it!

  • Download and execute the latest 64bit installer (the most recent wsltty-*-install-x86_64.exe file)
  • After installing, you will get several ways to open a terminal:
    • Double-click on the WSL terminal icon on the desktop
    • UUbuntu terminal and WWSL Terminal in the Start menu
      • There is also a WWSLtty folder, than you don't really need
  • Open a terminal and right-click in it to check the available options
    • You can access even more options with CTRL+right-click
    • You can cycle between the open WSLtty terminals with CTRL+Tab and Shift+CTRL+Tab
  • Technical stuff (on the Mintty wiki)

The new Windows Terminal

Microsoft is working on a powerful replacement of the old cmd terminal! Check Windows Terminal, Console and Command-Line @ github

Note: the Windows Terminal looks really promising, but will be nice when there is a GUI for editing the options (rather the editing a json file with a text editor…) and a way to select xterm-style copy-pasting. See Feature request: add xterm-style select/copy/paste options

Terminals started from Linux

You can install additional graphical terminals inside the Linux running in WSL, but you will need to have a running X server if you want to open them. In these terminals, the usual Linux copy/paste rules will apply!

  • Install with: apt-get install xterm
  • Start from another terminal with: xterm &
  • Install with: apt-get install xfce4-terminal
  • Start from another terminal with: xfce4-terminal &

Location of the files

You can optionally read the detailed WSL File System Support page if you want to (try to) understand how things work and how both systems can share files.

Linux files seen from Windows

  • You can access the Linux files in / from Windows by opening the virtual \\wsl$ path in the Windows explorer (since Windows build 18342)
    • Your Linux home directory is located in \\wsl$\Ubuntu\home\<your_login>
  • The content of the Ubuntu / directory is actually located in the following hidden sub-directory of the user's Windows home directory: C:\Users\<your_login>\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc\LocalState\rootfs
Do not change Linux files in '/' from Windows! (it's safe only if you use the \\wsl$ path)

If you need to easily update files from both Linux and Windows, put them in a regular Windows directory (not in the hidden directory mentioned above, where the Linux system is installed)

Windows files seen from Linux

Note: When you are in an explorer window, you can open a Windows terminal with Linux by holding Shift and right-clicking on a directory and choosing Linux in the context menu.

The Windows partitions are mounted under /mnt in Linux:

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
rootfs          111G   30G   82G  27% /
none            111G   30G   82G  27% /dev
none            111G   30G   82G  27% /run
none            111G   30G   82G  27% /run/lock
none            111G   30G   82G  27% /run/shm
none            111G   30G   82G  27% /run/user
C:              111G   30G   82G  27% /mnt/c
H:              366G  138M  366G   1% /mnt/h

Read the Mounting disks and network drives section if you want to access remote server disks on your local network, or just want to access USB disks/sticks on your local computer.


  • The wslpath command can be used to make Windows↔Linux path conversion

Linux version installed

$ date
Thu Feb 20 11:18:57 CET 2020

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.4 LTS
Release:        18.04
Codename:       bionic

$ cat /proc/version
Linux version 4.4.0-18362-Microsoft ( (gcc version 5.4.0 (GCC) ) #476-Microsoft Fri Nov 01 16:53:00 PST 2019

$ uname -a
Linux some_machine_name 4.4.0-18362-Microsoft #476-Microsoft Fri Nov 01 16:53:00 PST 2019 x86_64 x86_64 x86_64 GNU/Linux

Ubuntu packages installed

$ dpkg --list
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                  Version         Architecture    Description
ii  accountsservice       0.6.45-1ubuntu1 amd64           query and manipulate user account information
ii  acl                   2.2.52-3build1  amd64           Access control list utilities
ii  acpid                 1:2.0.28-1ubunt amd64           Advanced Configuration and Power Interface event
ii  adduser               3.116ubuntu1    all             add and remove users and groups

ii  xterm                 330-1ubuntu2    amd64           X terminal emulator
ii  xxd                   2:8.0.1453-1ubu amd64           tool to make (or reverse) a hex dump
ii  xz-utils              5.2.2-1.3       amd64           XZ-format compression utilities
ii  zerofree              1.0.4-1         amd64           zero free blocks from ext2, ext3 and ext4 file-s
ii  zlib1g:amd64          1:1.2.11.dfsg-0 amd64           compression library - runtime

$ dpkg --list > /mnt/c/Scratch/jyp/pkg_initial_201601.txt
$ wc -l /mnt/c/Scratch/jyp/pkg_initial_201601.txt
628 /mnt/c/Scratch/jypeter/pkg_initial_201601.txt

Full (example) list of installed packages: pkg_initial_201601.txt

Update ubuntu

Use the following to update your ubuntu installation:

$ sudo -s
$ apt-get update
$ apt-get upgrade

Managing WSL

This is just place to store some technical information, that will probably not be needed by most people

Getting ready for some real work

We often assume below that you are using the root account (sudo -s), or sudo when executing the apt* installation commands, and othe admin commands

Specifying correctly the display language

WSL will automatically try to use in the terminals the same language as the one used by the Windows 10 computer (ref), but this could lead later to some difficult to debug side-effects when you connect to remote Linux servers (e.g. the sort command may give different results !).

It is safer to force the system to use a standard English version

$ sudo update-locale LANG=en_US.UTF8
$ echo $LANG

Package management

apt-get tutorial if you are more used to Fedora/RedHat yum/dnf and rpm packages

  • Install the aptitude package manager: apt-get install aptitude
  • Install the synaptic package manager: aptitude install synaptic

Useful commands

  • dpkg -l: list installed packages
  • dpkg -L package_name: list files installed from package_name
  • dpkg -S path/command: name of the package used to install path/command


$ dpkg -l | grep -i wsl
ii  ubuntu-wsl                      1.417.3                            amd64        Ubuntu on Windows tools - Windows Subsystem for Linux integration
ii  wslu                            2.3.2-0ubuntu2~18.04.3             all          collection of utilities for the Windows 10 Linux Subsystem

$ dpkg -L wslu

Using an X server

You will need to have an X server running locally on your Windows 10 machine if you want to display graphics generated by the Linux running locally, or on a remote server. Applications running in text mode only (e.g. vi) do not require a running X server.

You will get a Can't open display error if no server is running (even if the DISPLAY variable is correctly defined)

your_login@your_machine:~$ echo $DISPLAY
your_login@your_machine:~$ xterm &
xterm: Xt error: Can't open display: localhost:0.0
[Everything is fine after starting a local X server]
jyour_login@your_machine:~$ xterm &
[1] 55

Installing an X server

The X server will allow you to display graphical windows (i.e. X windows) from remote servers or from your local WSL+Ubuntu

After the X server is installed and running, some graphical applications and images (or the text displayed by those applications) may appear blurry. This is due to some servers or some Linux applications not handling high resolution (HiDPI) screens correctly

X410 has several options for this (see Running X410 on HiDPI Screens) but it may also work correctly with non commercial applications

Installing VcXrsv

VcXrsv is pre-installed on the LSCE computers!

Type: free

Download the installer from VcXrsv and install VcXrsv.

VcXrsv Configuration

You need to configure VcXrsv to work in multiple windows mode. The following steps will show you how to create a shortcut on your desktop to start VcXrsv in this appropriate mode

  • Start Xlaunch: StartVcXrsvXlaunch
  • Check Multiple windows (the default choice) then Next
  • Check Start no client then Next
  • Keep the default Clipboard settigs, uncheck Native opengl (not sure about that) then Next
  • Click on Save configuration and save an X_Server.xlaunch configuration file on your Desktop, then Terminate. You should now have a new X_Server icon/shortcut on your Desktop
  • Click on the new X_Server icon, and check that an X icon appears in the right side of the taskbar (you may have to look for it in the Display hidden icons pull-up menu)
    • Note: you can right-click on the X icon and select Exit… if you need to quit the X server
  • Note: if you notice later that the content of some displayed X windows appear blurry, see if you can fix the compatibility settings, or try to use x410.
  • You are now ready, if you only need VcXrsv to display graphical windows from remote servers
  • The following steps allow you to test the X server in a local WSL+Ubuntu terminal. Do not set the DISPLAY variable yourself when you are connected to a remote server with ssh!
    • Open a local terminal (in WSL+Ubuntu)
    • Type export DISPLAY=localhost:0.0
    • Type xterm and check that a new xterm terminal appears

Installing x410

Type: commercial

x410 is a low cost commercial X server that can be directly installed from the Microsoft store. Once installed, it will be automatically updated by the Microsoft Store application.

Starting, configuring and exiting X410: you can start X410 by clicking on it in the Windows Start Menu, or choose to Automatically Start X410 on Login

  • Note: nothing actually happens when you start X410, as it is just waiting to display graphics! You will just get a new X icon in the hidden icons of the taskbar.
  • You can configure (and exit) X410 by right clicking on its X icon

Installing MobaXterm

Type: commercial

Available at MobaXterm, not tested. This seems to be more than just an X server, and may be an overkill if you just need an X server

Configuration (in your local Linux account)

  • Set the DISPLAY variable in the shell (by hand, or in the bash shell init file)
    • export DISPLAY=localhost:0.0
    • Warning! export DISPLAY=:0.0 will also work for using graphical windows locally, but will fail when trying to open a window on a remote computer, with a connect /tmp/.X11-unix/X0: No such file or directory error message (source)
  • FIXME Need to determine if/when export LIBGL_ALWAYS_INDIRECT=1 is useful
    • it breaks glxgears with x410


You can skip this! m(

Adding useful packages

Reminder: you need to use the root account (with sudo -s) in order to use the following commands

$ apt-get install gcc libglu1-mesa mesa-utils libsm6 x11-apps

# Check the "Terminals started from Linux" section
# if you need to install extra terminals

# Install emacs
$ apt-get install emacs

# Install pdf (evince) and image (eog) viewers
$ apt-get install evince eog

# Install wslu to improve the Windows<->Linux communication
$ apt-get install wslu

# The packages below are useful for dealing with climate data
# in netCDF files (and are also requirements of CLIMAF)
$ aptitude install imagemagick nco cdo netcdf-bin ncview exiv2

Updating WSL and ubuntu

You don't have to worry about the Upgrade section if you have just installed WSL+Ubuntu, because you are already using the latest Ubuntu stable release!


Nothing to do! WSL is automatically updated, provided you have enabled the Get updates for other Microsoft products option

WSL command line options

Updating ubuntu

The Ubuntu 16.04.3 LTS that was initially installed from the Windows Store when the test computer was running Win 10 1709 was automatically updated to Ubuntu 18.04.2 LTS when the computer was updated to Win 10 1809.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.2 LTS
Release:        18.04
Codename:       bionic

We also ran the do-release-upgrade command to complete the upgrade (from 16.04 to 18.04) [ More info from WSL team - more info from Ubuntu ]

And we then ran the usual upgrade commands. These commands can be run any time for updating the installed packages

$ sudo -s
$ apt-get update
$ apt-get upgrade

Full list of the resulting installed packages, generated with

$ dpkg --list >$ dpkg --list > /mnt/h/Scratch/jyp/pkg_190221.txt
$ wc -l /mnt/h/Scratch/jyp/pkg_190221.txt
578 /mnt/h/Scratch/jyp/pkg_190221.txt

Upgrading ubuntu

You can skip this section if you have just installed ubuntu, since you are already running the latest stable release available

The updates are for maintaining the same version of ubuntu (e.g. you go from version 18.04.2 to 18.04.5), while upgrades are for going from one major version to the next (e.g 16.xx18.xx20.xx). We try to only use the stable major releases, that have an even version number.

We use the LTS versions (Long Time Support) to ensure even more stability, which means that we will get updates of a given major release for quite some time after the next major release is available, so it is not mandatory to updgrade ubuntu if you are still receiving updates for the release you use

There should not be any risk, but it may be a good idea to create a backup of your current ubuntu before upgrading it!

Use sudo for each command below, or just become root by using sudo su -

  • Launch the upgrade with the do-release-upgrade command and follow the instructions
    • if you get a There is no development version of an LTS available message, use do-release-upgrade -d
    • if you get a Please install all available updates for your release before upgrading message, use apt-get dist-upgrade and then try do-release-upgrade -d again (see How to Solve the Upgrade Ubuntu Install Updates Error)
    • if you get sleep: cannot read realtime clock: Invalid argument error, temporarily replace the sleep binary with an executable empty file. Do not forget to restore the original sleep command after the upgrade!!
      • # sleep 1
        sleep: cannot read realtime clock: Invalid argument
        # mv /bin/sleep /bin/sleep.back
        # ls -l /bin/sleep.back
        -rwxr-xr-x 1 root root 35000 Jan 18  2018 /bin/sleep.back
        # touch /bin/sleep
        # chmod +x /bin/sleep
        # sleep 1
      • Note: you may have to use the empty sleep command trick again, if the sleep command itself is updated and breaks the upgrading process again. Do not forget to restore the original sleep command after the upgrade!!
        Restarting services possibly affected by the upgrade:
          cron: stopping...sleep: cannot read realtime clock: Invalid argument
        dpkg: error processing package libpam0g:amd64 (--configure):
         installed libpam0g:amd64 package post-installation script subprocess returned error exit status 1
        E: Sub-process /usr/bin/dpkg returned an error code (1)
        # ls -l /bin/sleep
        -rwxr-xr-x 1 root root 39256 Sep  5  2019 /bin/sleep
        # mv /bin/sleep /bin/sleep.back2
        # touch /bin/sleep
        # chmod +x /bin/sleep
    • Do not forget to restore the correct sleep executable, if you had to move it
      • # ls -l /bin/sleep*
        -rwxr-xr-x 1 root root     0 Aug 23 23:57 /bin/sleep
        -rwxr-xr-x 1 root root 35000 Jan 18  2018 /bin/sleep.back
        -rwxr-xr-x 1 root root 39256 Sep  5  2019 /bin/sleep.back2
        # cp -p /bin/sleep.back2 /bin/sleep
        # ls -l /bin/sleep*
        -rwxr-xr-x 1 root root 39256 Sep  5  2019 /bin/sleep
        -rwxr-xr-x 1 root root 35000 Jan 18  2018 /bin/sleep.back
        -rwxr-xr-x 1 root root 39256 Sep  5  2019 /bin/sleep.back2

Advanced configuration

Get Linux configuration files

  • You can either adapt your existing Linux configuration files (.profile, .bashrc, …) from another Linux computer, or download some example files in your WSL home directory and use (and improve) them as suggested below (or as you wish)
    • $ cd
      $ scp -pr <your_login> .
    • You get a default .bashrc file in your home directory when your WSL account is created. Add the following line at the end of ~/.bashrc to use what is defined in the downloaded WSL_config directory:
      source ~/WSL_config/
    • If you use the emacs text editor, you can use your own .emacs configuration file, or get an example configuration file the following way:
      • $ cd
        $ ln -s WSL_config/emacs .emacs
      • Font configuration (type, size, …): FIXME
  • You can either copy the full .ssh directory of your Linux account, or just get the private key files:

This assumes that you have already created a private/public ssh key pair and that the private key is available somewhere in the Windows 10 computer

ssh from WSL

Authorizing ssh to use old dsa keys

dsa ssh keys are disabled by default (becoming obsolete). ssh will ask for your password even if you have a ~/.ssh/id_dsa file. ssh -v will print Skipping ssh-dss key /home/<your_login>/.ssh/id_dsa - not in PubkeyAcceptedKeyTypes. The solution is to generate a new couple of public/private keys not based on dsa encryption, or to use the user ssh config file to authorize dsa (source)

  • Add PubkeyAcceptedKeyTypes +ssh-dss to ~/.ssh/config (before the HOST sections)
  • Make sure the config file has the correct access rights: chmod 600 config
Using Putty Pageant as an ssh agent

This assumes that you have installed the full Putty package (with the msi installer), converted your private ssh key with PuTTYgen, and unlocked the converted ssh private key in Pageant.

The converted ssh private key is located in a Windows 10 folder

  • Download the required binaries from the weasel-pageant github page and extract them to a Windows directory, e.g. C:\Utils\weasel-pageant-x.x
  • Add the following line to your ~/.bashrc file:
    eval $(/mnt/c/Utils/weasel-pageant-x.x/weasel-pageant -rb -a $HOME/.weasel-pageant.sock)
    • This is done by default in the ~/WSL_config/ if you have downloaded and adapted it
  • Open a new terminal:
    • Type ssh-add -l: it will display either The agent has no identities, or as many lines as you have entered keys in Pageant
    • Type ssh user@host to connect to a computer where you have your public key

Note: the other similar solutions are ssh-agent-wsl (the key is stored in the Windows ssh-agent instead of Pageant) or wsl-ssh-pageant

Using Ubuntu as an ssh-agent

The ssh key (and other ssh settings) are in the ~/.ssh directory of your WSL+Ubuntu account

This is the most simple setting, but there will be one running ssh-agent per terminal, and the key will be stored independently for each terminal (which means that you will have to type ssh-add and your pass-phrase for each terminal)

  • It's not possible by default to add a key to ssh-agent ('ssh-add' will print Could not open a connection to your authentication agent)
  • If you want to use ssh-add in a terminal, you first need to type eval `ssh-agent -s` in the (or eval $(ssh-agent))
    • In that case, it's just easier to add eval $(ssh-agent) to the .bashrc file!
      • This is done by default in the ~/WSL_config/ if you have downloaded and adapted it
Notes & TODO

ssh to WSL

FIXME Maybe check OpenSSH-Server connection issues

Maybe it could be useful to do a ssh from the Win10 part of the machine to the WSL part, and from outside the machine to the WSL part

It would probably already be enough to enable the ssh server on Win10 (the ssh 1709 release beta features are now officially in Win10)

Google search: wsl ssh

Creating shortcuts to Linux programs on the Windows desktop

  • Install wslu (A collection of utilities for WSL) if it is not already installed
    • apt-get install wslu
  • Have a quick look at the wslu github page and wiki to find about the available tools (that you may need later)
  • You can create a shortcut by using wslusc in any Linux terminal
    • e.g. you can create a shortcut on the Windows desktop to start emacs (in WSL!) with:
      wslusc -g emacs
      • This will make it easier to start emacs, but since this is a graphical Linux application, you need to have an X server running before you click on the emacs shortcut!
  • You can optionally get some information about the technical details

Mounting disks and network drives

By default, the local disks and the external USB disks available (and decrypted!) when WSL is started (i.e. when the first WSL terminal is opened) are automatically available (mounted) in /mnt : the content of C:\ is available in /mnt/c, etc… The list of available disks is refreshed when the Windows session is restarted (the user logs out and in, or Windows is rebooted) or when just WSL is restarted.

Extra local disks or network drives (what you can access by opening \\dfshost\dfs\ in the file explorer when you are on the LSCE network) can be either mounted on the fly with the mount command, or automatically by configuring the /etc/fstab file.

You will access the network drives with the access rights you have in the current Windows session (and you may have to access the drives in Windows before you can mount them in WSL)

Warning! In all cases, the owner, groups and permissions displayed may not be accurate (but the actual access rights will apply).

  • the user/group of the files may appear as your_login/your_login or root/root. Example of a local file belonging to the current Windows jypeter user, and a system file
    • $ ls -l /mnt/c/Users/jypeter/Desktop/File_on_Desktop.txt
      -rwxrwxrwx 1 jypeter jypeter 0 Jan 21 11:50 /mnt/c/Users/jypeter/Desktop/File_on_Desktop.txt
      $ ls -l /mnt/c/Windows/notepad.exe
      -r-xr-xr-x 3 jypeter jypeter 181248 Mar 19  2019 /mnt/c/Windows/notepad.exe
  • the access rights may appear as rwxrwxrwx even if the actual rights are more restrictive. Example after mounting the LSCE /home/scratch01 disk
    • # File access rights seen from WSL+Ubuntu
      $ ls -l /mnt/scratch01/jypeter/
      -rwxrwxrwx 1 root root 2755154 Jan 13 15:10 /mnt/scratch01/jypeter/
      # Actual access rights (on the Linux server)
      >ls -l /home/scratch01/jypeter/
      -rw-r--r-- 1 jypeter lsce 2755154 Jan 13 15:10 /home/scratch01/jypeter/
      # You can't change the access rights from WSL+Ubuntu, but you can remove a file, or create a new one
      $ chmod 600 /mnt/scratch01/jypeter/
      chmod: changing permissions of '/mnt/scratch01/jypeter/': Operation not permitted
      $ rm /mnt/scratch01/jypeter/
      $ ls -l /mnt/scratch01/jypeter/
      ls: cannot access '/mnt/scratch01/jypeter/': No such file or directory
      $ touch /mnt/scratch01/jypeter/new_file_from_wsl.txt
      jypeter@lsce5203:/mnt/scratch01/jypeter$ ls -l /mnt/scratch01/jypeter/new_file_from_wsl.txt
      -rwxrwxrwx 1 root root 0 Jan 21 11:37 /mnt/scratch01/jypeter/new_file_from_wsl.txt
      # The new file has the correct (default) access rights on the Linux server
      >ls -l /home/scratch01/jypeter/new_file_from_wsl.txt
      -rw-r--r-- 1 jypeter lsce 0 Jan 21 11:37 /home/scratch01/jypeter/new_file_from_wsl.txt

Enabling metadata

Some access rights handling can be slightly improved by automatically enabling the metadata mount option. This will allow you to use chmod/chown on local NTFS disks (disks directly connected to your computer, e.g. /mnt/c/Users/your_login).

  1. become root in a terminal with: sudo -s
  2. create a /etc/wsl.conf with the following content:
    options = "metadata"

You need to restart WSL+ubuntu to activate the new content of /etc/wsl.conf. See below an example of the mount -l output:

  • Before: C: on /mnt/c type drvfs (rw,noatime,uid=1000,gid=1000,case=off)
  • After enabling metadata: C: on /mnt/c type drvfs (rw,noatime,uid=1000,gid=1000,metadata,case=off)

Optional: more details about wsl.conf in WSL launch settings, How to use wsl.conf and metadata and access rights management

On-the-fly mount

You have to create a mount point in the existing /mnt directory and then use the mount command

# Must be root for most 'mount' related commands
$ sudo -s

# Create the mount point (once), e.g. for accessing /home/scratch01 on the local LSCE servers
# This works when the Windows 10 computer is on the LSCE network
$ mkdir /mnt/scratch01

# Mount the remote disk
$ mount -t drvfs '\\dfshost\dfs\scratch01' /mnt/scratch01

# List the mounted disks
$ mount -l
\\dfshost\dfs\scratch01 on /mnt/scratch01 type drvfs (rw,relatime,case=off)

# Unmount the disk, or just shutdown Windows or WSL when you are finished
$ umount /mnt/scratch01

If you connect a USB disk/stick and windows sees it as a new J:\ drive, you can also manually mount it

$ sudo -s

# Create the mount point (once)
$ mkdir /mnt/j

# Mount the USB disk
$ mount -t drvfs J: /mnt/j

# Unmount the disk, or just shutdown Windows or WSL when you are finished
$ umount /mnt/j

Automatic mount

The disks defined in /etc/fstab will be automatically mounted when you start WSL and if they are actually accessible from your Windows session (e.g. \\dfshost\dfs can only be accessed from the LSCE network)

You need to add 1 line per mount point to /etc/fstab, and create (once) the directories that will be used for mounting the disks

$ sudo -s

# Create the mount points (once)
# The example below is to access the LSCE /home/users and /home/scrath01 disks
$ mkdir /mnt/users /mnt/scratch01

# Make a backup copy of /etc/fstab before modifying it (for safety reasons!)
$ cp -p /etc/fstab /etc/fstab.bak

# Add lines to /etc/fstab associating mount points and directories
$ cat /etc/fstab
LABEL=cloudimg-rootfs   /        ext4   defaults        0 0
\\dfshost\dfs\users /mnt/users drvfs defaults 0 0
\\dfshost\dfs\scratch01 /mnt/scratch01 drvfs defaults 0 0

# Try to mount all the disks in /etc/fstab
$ mount -a

# Check the result
$ mount -l
\\dfshost\dfs\users on /mnt/users type drvfs (rw,relatime,case=off)
\\dfshost\dfs\scratch01 on /mnt/scratch01 type drvfs (rw,relatime,case=off)

Accessing remote file systems with sshfs


It seems this can be done with a combination of WinFsp and SSHFS-Win (see SSHFS remote directory mounting syntax for details

Extra resources

Useful mount options:

  • mount -a (must be root): mount everything specified in /etc/fstab
  • umont /mnt/scratch01 (must be root): unmount the disk accessible through /mnt/scratch01
  • mount -l: list all the mounted disks and the mount options (useful when you are using the default mount options and want to know which options were actually applied)

Useful links (used for writing this section):

Rebooting WSL

It is not possible to stop or reboot WSL like a regular Linux computer

  • shutdown -r now will generate an error message
  • WSL keeps on running even when all the Linux terminals are closed

Shutting down or rebooting the Windows computer will of course stop WSL but it's useful to be able to just stop/restart WSL in order to:

  • force WSL to recognize new disk drives and make them available as /mnt/<new_drive_letter
  • force WSL to recognize drives that were still encrypted when the first WSL terminal was opened

WSL can be stopped the following way. Warning: ​all the open terminals and running processes ​will be terminated!

  • from a Windows terminal (cmd, PowerShell, … no need to run as administrator):
    • Get the name of the installed (and running) Linux: wsl --list --verbose
    • Stop this instance of Linux (e.g. if it is named Ubuntu): wsl --terminate Ubuntu
    • or Stop all the currently running Linux distributions: wsl --shutdown

Creating a backup of the Linux running in WSL

There are several types of WSL related directories that you may want to back up:

  • Your Linux home directory (/home/<your_login>), or some specific sub-directories of the Ubuntu running in WSL (sub-directories of /): all these files are located in a hidden sub-directory of you Windows directory, and the best way to save them is probably to create a tar file from Linux, and put this tar file in a specific Windows WSL backup folder (we will use below the directory /mnt/c/Scratch/<your_login> or c:\Scratch\<your_login>)
    • $ cd /home
      $ du -sh $USER
      232K    <your_login>
      # We assume below that there is an existing /mnt/c/Scratch/<your_login>/ directory
      # It's a WINDOWS directory C:\Scratch\<your_login>
      $ tar cfz /mnt/c/Scratch/$USER/${USER}_home_`date +%y%m%d_%H%M`.tgz $USER
      # Check the size of the new (and existing old) backup(s)
      $ ls -ltr /mnt/c/Scratch/$USER/${USER}_*.tgz
      81K Jan 21  2020 /mnt/c/Scratch/<your_login>/<your_login>_home_200121.tgz
      93K Aug 22  2020 /mnt/c/Scratch/<your_login>/<your_login>_home_200822_1151.tgz
      95K Feb 24 12:09 /mnt/c/Scratch/<your_login>/<your_login>_home_210224_1209.tgz
  • Regular Windows folders where you store data used by WSL: you can use tar in a Linux terminal, as above, or use any usual way of backing up Windows files (drag and drop, some specific backup software)
  • The full Linux/Ubuntu installation running in WSL (based on How can I back up my WSL distros?). The following steps will save the full installation in a tar file, that can be used later for restoring the full installation (restoration not tested yet)
    • Open a Windows terminal (preferably a PowerShell if you need easy copy/paste)
      The Windows terminal is where you will type the wsl commands shown below
    • Determine the name of the current Linux installation used in WSL (and see if it is running, and using WSL 1 or WSL 2)
      • > wsl --list --all
        Distributions du sous-système Windows pour Linux :
        Ubuntu (par défaut)
        > wsl --list --verbose
          NAME      STATE           VERSION
        * Ubuntu    Running         1
      • > wsl --list --verbose
          NAME      STATE           VERSION
        * Ubuntu    Running         1
        > wsl --shutdown
        > wsl --list --verbose
          NAME      STATE           VERSION
        * Ubuntu    Stopped         1
    • Export the current Linux to a tar file:
      •  > wsl --export Ubuntu C:\Scratch\<your_login>\<your_login>_ubuntu-<ubuntu_version>-full_<some_date>.tar
    • You can optionally open a new terminal (this will start again WSL+Ubuntu) to get some information about the created file (size and number of saved files/directories), and compress it in order to save some disk space
      • $ cd /mnt/c/Scratch/<your_login>
        $ ls -ltrh *ubuntu*tar*
        976M Jan 21  2020 <your_login>_200121.tar.gz
        2.8G Aug 22  2020 <your_login>-16.04-full_200822.tar
        3.4G Feb 24 14:06 <your_login>-20-04-1-full_210224.tar
        # Determine the number of files/directories in the backup
        $ tar tvf <your_login>-20-04-1-full_210224.tar | wc -l
        $ gzip *ubuntu*.tar
        $ ls -ltrh *ubuntu*tar*
        976M Jan 21  2020 <your_login>_200121.tar.gz
        1.2G Aug 22  2020 <your_login>-16.04-full_200822.tar.gz
        1.8G Feb 24 14:06 <your_login>-20-04-1-full_210224.tar.gz

Restoring a WSL backup

FIXME Read How to Export and Import Your Linux Systems on Windows 10 and Export and Import WSL Linux Distro in Windows 10 and similar threads

FIXME Check if WSL Manager is maintained and can be useful

This assumes that you have followed the steps above to create a full backup of your Linux distribution in a ubuntu_<your_login>_<some_date>.tar file. This file can theoretically be restored with:

  • wsl --import <DistributionName> <InstallLocation> ubuntu_<your_login>_<some_date>.tar
    • Note: found a page mentioning that you should be in a terminal with admin rights when using --import
    • Can we use the same <DistributionName> (e.g. Ubuntu) as the one we are trying to restore without first removing it with unregister (Unregister and reinstall a distribution)?
    • If we use a new distribution name, it will probably not appear anymore in the Microsoft Store and will not be updated. Is this a problem?
    • It seems we can use <InstallLocation> to install anywhere! What should we do if we want to restore to the default location (in the hidden directory)?
      • Can we install out of the current user's Windows folder?
      • Can we install out of C:\?
    • Can we restore (clone) a backed up Linux distribution on another Windows 10 computer for another user?
      • if the default user (and its password) has to be changed, you probably have to follow the steps to reset the Linux password and find a way to create a new account when the root password is activated

Uninstalling WSL

Not too sure about this part…

  • Make a backup of whatever you had in your Ubuntu home directory, and all the files and settings that are not in the /mnt directories
  • Find how to unregister Ubuntu on the Manage and configure Windows Subsystem for Linux page
  • and then disable WSL???

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other/win10wsl.txt · Last modified: 2021/02/24 14:44 by jypeter