GNU Screen in WSL

When running the screen command in a WSL (Windows Subsystem for Linux) Debian-based environment, you may get this error:

$ screen -ls
Cannot make directory '/run/screen': Permission denied

Or even this:

$ screen -ls
Cannot make directory '/run/screen': File exists

You can safely remove that directory if you don't need it:

sudo rm /run/screen

Then set the SCREENDIR environment variable as follows:

export SCREENDIR=$HOME/screens

And it should work now:

$ screen -ls
No Sockets found in /home/john/screens.

To make the SCREENDIR environment variable permanent, add it to your configuration file:

nano ~/.bashrc

Just put this at the end of the file:

# Set the GNU Screen environment variable.
export SCREENDIR=$HOME/screens