Windows terminal compatibility for the ACLI Shell

Owned by Gabriela Costa, created
Last updated: Jun 20, 2023 by Robert Bergman
3 min read

 Problem

Many terminal apps utilize the Windows-native Console Host (conhost.exe) executable for implementation. Under Windows 10, conhost.exe exhibits a bug that limits ACLI Shell functionality.
In this environment, conhost.exe incorrectly interprets a critical VT100 control sequence as a VT52 sequence, which breaks the ACLI Shell interactive renderer. As a result, terminal apps that rely on conhost.exe executable under Windows 10 fail to function as designed.

The issue is rectified in the conhost.exe implementation shipped with Windows 11 as well as when running apps in Windows Terminal and other VT100-compliant terminal emulators (e.g., ConEmu, CMDER, Alacritty, and WezTerm) capable of running on Windows 10.

 Solution

The Windows terminal compatibility table shows how to handle environment variables on Windows 10 and Windows 11 for ACLI 10.6 and earlier and ACLI 11.0

Windows terminal compatibility

Windows Version

Terminal App

ACLI Version

Solution

Windows Version

Terminal App

ACLI Version

Solution

Windows 10

Console Host (conhost.exe) and any terminals that depend on it

10.6.0 and earlier

Do not use!

Windows 10

Windows Terminal

10.6.0 and earlier

No special setup required

Windows 10

Any other VT100-compliant terminal

(WezTerm, Alacritty, ConEmu, CMDER, etc)

10.6.0 and earlier

Manually set WT_SESSION=1 (see below)

Windows 10

Windows Terminal, WezTerm, Alacritty, ConEmu, CMDER

11.0.0 and later

No special setup required

Windows 10

Any VT100-compliant terminal not listed above

11.0.0 and later

Manually set WT_SESSION=1 (see below)

Windows 11

Any terminal

11.0.0 and later

No special setup required

Applying the WT_SESSION workaround when indicated by the above table:

  1. Open the environment variables settings on your system.

  2. Create a new environment variable named WT_SESSION and set its value to any non-empty string (e.g., 1).

  3. Save the changes, and restart your terminal application.

  4. Launch the ACLI shell.

Remember that the shell proper functioning depends on the correct implementation of the VT100 specification of the terminal emulator.
Setting the WT_SESSION environment variable alone may not be sufficient for the shell to function correctly.

If the terminal emulator still uses the broken conhost exe, users may notice that the terminal renders garbage on the screen as soon as the app provides completions.

To ensure the best experience with the ACLI shell, it is recommended to use a fully VT100-compliant terminal emulator or upgrade to Windows 11 or to use Microsoft’s Windows Terminal.

Other terminal applications

The supported terminal emulators on Windows 10 are:

  • Windows Terminal

  • WezTerm

  • Alacritty

  • ConEmu

  • CMDER

If you know of another VT100-compliant terminal on Windows 10, you can test it using the instructions given for ACLI 10.6.0 and earlier.

If the shell works, contact us so that we can add official support for that terminal.

Additional environment variables

Depending on your requirements and specific cases, additional environment variables for Shell configuration are available and described in the Environment Variables Table.

Environment variable

Description

Environment variable

Description

ACLI_SHELL_GLYPHS

Value is one of ascii, unicode, powerline, or nerdfont.

The shell automatically sets the glyph set to ascii when either the ConEmu or Cmder terminals are detected on Windows in ACLI v11

ACLI_SHELL_THEME

Value is one of the themes available in the shell (or a custom theme).

NOTE

  • Some terminals may have complex color schemes, you can create your own color scheme.

  • To display the available themes type /settings theme set .

ACLI_SHELL_CACHE_DIR

It allows you to specify where to store the shell cache files.

ACLI_SHELL_CONFIG_DIR

It allows you to specify where to store the shell config files.

ACLI_DEFAULT_TABLE_STYLE

This variable is useful, if you do not have full unicode support in the terminal:

  • set the value to TEXT to get acli to use ascii chars rather than unicode when rendering tables. It also forces the shell to act as if ACLI_SHELL_GLYPHS was set with the value ascii.

ACLI_SHELL_DEBUG

Set the value to 1 to generate debug output.

Set the value to 2 to add trace information.

ACLI_SHELL_LOG

It sends the debug to a log rather than a terminal. This environment variable is recommended if you use the debug variable ACLI_SHELL_DEBUG .

The value for this variable is the path to the log file where the debug and trace information is to be sent: an empty string value uses the default path acli-shell.log