PowerShell中如何捕获bittrex-api.ps1的输出至变量供主脚本使用？

Hey there! I’ve dealt with this exact scenario before—capturing Write-Host output from a called script can be tricky because it doesn’t flow through the standard success stream by default. Let’s break down how to do this properly based on your PowerShell version:

For PowerShell 5.1 or Newer #

Starting in PowerShell 5.0, Write-Host writes to the Information Stream (stream number 6) instead of directly to the console. To capture this, you can redirect the information stream to the success stream using 6>&1 when calling the script:

# Capture all output (including Write-Host messages) into a variable
$bittrexResults = .\bittrex-api.ps1 6>&1

Now you can filter the variable to extract the specific error message you’re looking for:

# Find lines containing the Bittrex error marker
$capturedError = $bittrexResults | Where-Object { $_ -match 'BITTREX ERROR:' }

# Use the error in your main script
if ($capturedError) {
    Write-Error "API call failed: $($capturedError -replace 'BITTREX ERROR: ', '')"
    # Add your error handling logic here (e.g., log to file, retry, etc.)
}

For PowerShell 4.0 or Older #

In older PowerShell versions, Write-Host writes directly to the console host, so stream redirection won’t work. Instead, you can temporarily redirect the console output to a string writer:

# Save the original console output stream
$originalConsoleOut = [Console]::Out

# Create a string writer to capture output
$stringWriter = New-Object System.IO.StringWriter
[Console]::SetOut($stringWriter)

# Execute the Bittrex API script
.\bittrex-api.ps1

# Restore the original console output
[Console]::SetOut($originalConsoleOut)

# Get the captured output as a string
$bittrexResults = $stringWriter.ToString()

# Filter for the error message (split into lines if needed)
$capturedError = $bittrexResults -split "`n" | Where-Object { $_ -match 'BITTREX ERROR:' }

Key Notes #

• If the Bittrex script also uses Write-Error for errors, you’ll need to redirect the error stream too with 2>&1 (e.g., .\bittrex-api.ps1 6>&1 2>&1).
• The 6>&1 syntax merges the information stream into the success stream, so your variable will contain all output from the script—use filtering to isolate what you need.

内容的提问来源于stack exchange，提问作者Mister Iks