Is there a way to preserve ANSI control codes in PowerShell command output?

In PowerShell, is there a way to preserve the ANSI control codes used to convey color information to the console when assigning a program's output to a variable?

For instance, I use Test Kitchen which provides colored output unique to each suite of tests to run. When I run kitchen create INSTANCE, I get output in several colors. However, if I assign the output to a variable, or pipe it to another cmdlet such as Tee-Object, that color information is lost. It seems that PowerShell strips this information out when the result is sent down the pipeline or assigned to a variable:

kitchen create INSTANCE           # Colored output

$output = kitchen create INSTANCE
Write-Host $output                # Color information is lost

Curiously though, I can implement control codes in my own strings and PowerShell is able to honor them when Virtual Terminal is enabled. These survive variable assignment, unlike command output:

$output = "`u{001b}[31mHello"
Write-Host $output                # Results in colored output

So it seems that the color information is being stripped out only from a program's output, and only if the value is assigned or sent down the pipeline. Is there a way to preserve these control codes from external commands?

To add to your own answer:

• On Windows I'm not aware of any simple solutions, though perhaps there is a programmatic way to do what the script utility does on Unix-like platforms (see next point).

• On Unix-like platforms, you can use the script utility to make external programs believe they are connected to a terminal and thus make them produce colored output they would otherwise suppress:

  • script is not a POSIX-mandated utility, but it ships with at least some Linux distros, notably Ubuntu, as well as with macOS.
  • Notably, the macOS and Linux implementations use different syntax, as shown below.

Example:

• Note:

  • ls --color=auto is used as a readily available test command, because it exhibits the conditional coloring behavior.

  • ls --color=always would exhibit unconditional coloring behavior, and would therefore obviate the need for script - as such, ls is an example of a utility that does allow you to request unconditional coloring; ls --color=auto merely serves as a stand-in for utilities that do not.

  • The variable assignment below ($out = ...) is enclosed in (...) in order to pass the value being assigned through, so you'll see right away that the coloring is preserved.

• Linux

($out = script -qc 'ls --color=auto' /dev/null)

• macOS:

($out = script -q /dev/null ls --color=auto)