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powershell/PSAvoidUsingWriteHost is a PSScriptAnalyzer diagnostic emitted by tally for PowerShell snippets embedded in Dockerfiles.
PropertyValue
SeverityWarning
CategoryPSScriptAnalyzer
Auto-fixNo

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Description

The primary purpose of the Write-Host cmdlet is to produce display-only output in the host. For example: printing colored text or prompting the user for input when combined with Read-Host. Write-Host uses the ToString() method to write the output. The particular result depends on the program that’s hosting PowerShell. The output from Write-Host isn’t sent to the pipeline. To output data to the pipeline, use Write-Output or implicit output. The use of Write-Host in a function is discouraged unless the function uses the Show verb. The Show verb explicitly means display information to the user. This rule doesn’t apply to functions with the Show verb.

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How

Replace Write-Host with Write-Output or Write-Verbose depending on whether the intention is logging or returning one or more objects.

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Examples

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Problematic code

function Get-MeaningOfLife
{
    Write-Host 'Computing the answer to the ultimate question of life, the universe and everything'
    Write-Host 42
}

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Correct code

Use Write-Verbose for informational messages. The user can decide whether to see the message by providing the Verbose parameter. 
function Get-MeaningOfLife
{
    [CmdletBinding()]Param() # makes it possible to support Verbose output

    Write-Verbose 'Computing the answer to the ultimate question of life, the universe and everything'
    Write-Output 42
}

function Show-Something
{
    Write-Host 'show something on screen'
}

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More information

Write-Host

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Source

This rule documentation is adapted from Microsoft’s PSScriptAnalyzer documentation for AvoidUsingWriteHost, licensed under CC BY 4.0.