Tag: PowerShell

Ah, PowerShell—the Swiss Army knife of scripting languages. Just when you think you’ve explored all its tools, it unveils a new feature that makes you wonder how you ever lived without it. Today, we’re diving into one such feature that might have flown under your radar: pseudo-terminal support. If you’re moderately skilled in PowerShell, prepare to have your command-line experience elevated.

What on Earth Is Pseudo-Terminal Support?

In the realm of command-line interfaces, a pseudo-terminal (PTY) acts as a mediator between a user and the system, emulating a physical terminal. This allows for more sophisticated interactions with native commands, enhancing how input and output are handled within PowerShell.

Why Should You Care?

Traditionally, PowerShell has had limitations in capturing and managing the output of native commands. This often led to challenges in scripting and automation, especially when dealing with complex command-line tools. With pseudo-terminal support, these limitations are addressed, offering:

• Improved Output Handling
• Enhanced Interactivity
• Streamlined Automation

How Does It Work?

Pseudo-terminal support allows PowerShell to create a virtual terminal session for native commands. This means that when you execute a command, PowerShell can interact with it as if it were running in a standalone terminal, capturing all output and managing input more effectively.

Before Pseudo-Terminal Support

Imagine trying to run a command that requires interactive input, like ssh or cmd.exe /c pause. Before PTY support, PowerShell struggled to manage interactive commands cleanly. Here’s an example:

# Before PTY Support
Start-Process -FilePath "cmd.exe" -ArgumentList "/c pause" -NoNewWindow -Wait

In this case, interactive prompts might not behave as expected, or the output could be garbled, making automation difficult.

After Pseudo-Terminal Support

With PTY support enabled, PowerShell now handles such scenarios seamlessly, making it much more robust for interactive use cases. Here’s the improved approach:

# After PTY Support (Requires PowerShell 7.5+ and PTY enabled)
$session = New-Object System.Management.Automation.Host.PseudoTerminalSession
$session.StartProcess("cmd.exe", "/c pause")
$session.WaitForExit()

Now, PowerShell interacts directly with the pseudo-terminal, meaning smooth execution and proper handling of inputs and outputs.

Enabling Pseudo-Terminal Support

As of PowerShell 7.5, pseudo-terminal support is available as an experimental feature. To enable it:

1. Update PowerShell: Ensure you’re running PowerShell 7.5 or later.
2. Enable the Feature: Use the following command to turn on PTY support:

Enable-ExperimentalFeature -Name PseudoTerminalSupport

3. Restart PowerShell: Close and reopen your PowerShell session to apply the changes.

By leveraging pseudo-terminal support, PowerShell scripts become more capable of managing interactive commands and complex workflows, unlocking new possibilities for automation. Experiment with it and see how it fits into your toolkit!

Preview 2 has dropped! Let’s look at some of the major things that are coming in this preview.

First – let’s look at the breaking changes:

Breaking Changes

• Adjustments have been made to the -OlderThan and -NewerThan parameters for Test-Path, addressing issues when used with PathType and a date range​
• The default CatalogVersion for New-FileCatalog has been changed to 2​​
• Restrictions have been added to block help from network locations in restricted remoting sessions​

And now to the improvements:

Tab Completion Improvements

• Efforts led by contributors like @ArmaanMcleod have refined tab completion, including preventing fallback to file completion when tab completing type names and adding argument completers for various cmdlets like Set-StrictMode, Get-Verb, Start-Process, and more​

Web Cmdlets Improvements

• Fixes have been made to Invoke-WebRequest to ensure accurate size reporting when the -Resume parameter is specified​
• Web Cmdlets have been adjusted to allow WinForm applications to work correctly​

Other Cmdlet Improvements

• A range of cmdlet improvements and fixes, including for Test-Connection, Get-Service, and adding new parameters to New-Guid. For instance, New-Guid now supports -Empty and -InputObject parameters​

Engine Improvements

• Enhancements in the engine include telemetry for module imports, adjustments to module load telemetry, and fixes for regressions introduced by the WDAC logging feature​

Experimental Features

• Introduction of tilde expansion for Windows native executables, demonstrating PowerShell’s ongoing evolution and adaptation​

​.

PowerShell 7 introduces several lesser-known features that can significantly enhance your scripting prowess. Let’s dive into these hidden gems.

Ternary Operator for Concise Conditional Logic

PowerShell 7 brings the ternary operator (?:), a shorthand for simple if-else statements, allowing for more concise and readable code.

$result = ($value -eq 10) ? "Equal to 10" : "Not equal to 10"

Pipeline Parallelization with ForEach-Object -Parallel

The -Parallel parameter in ForEach-Object can dramatically improve performance by executing script blocks in parallel. Note that it requires the use of the -ThrottleLimit parameter to control the number of concurrent threads.

1..50 | ForEach-Object -Parallel { $_ * 2 } -ThrottleLimit 10

Simplified Error Viewing with $ErrorView and Get-Error

PowerShell 7 introduces a new view for error messages through the $ErrorView variable, which can be set to ConciseView for a more streamlined error display. Additionally, Get-Error provides detailed error information, perfect for troubleshooting.

$ErrorView = 'ConciseView'
Get-Error

Null Conditional Operators for Handling $null

The null conditional operators ?. and ?[] provide a safe way to access properties and methods or index into arrays when there’s a possibility of $null values, preventing unnecessary errors.

$obj = $null
$name = $obj?.Name  # Returns $null without throwing an error
$value = $array?[0] # Safely attempts to access the first element

The switch Statement Enhancements

PowerShell 7 enhances the switch statement with the -Regex and -File options, allowing pattern matching against regex expressions and simplifying file content parsing.

switch -Regex ($inputString) {
    'error' { Write-Output 'Error found' }
    'warning' { Write-Output 'Warning found' }
}

Coalescing Operators for Default Values

The null coalescing operators ?? and ??= simplify the process of providing default values for potentially $null variables, reducing the need for verbose if statements.

$name = $null
$displayName = $name ?? 'Default Name'

Automatic Unwrapping of Single-Element Arrays

A subtle but handy feature; when a command or expression returns an array with a single element, PowerShell 7 automatically unwraps it, eliminating the need for manual indexing to access the single item.

Enhanced JSON Handling with ConvertFrom-Json and ConvertTo-Json

Improvements to ConvertFrom-Json and ConvertTo-Json cmdlets include better depth handling and the ability to work with PSCustomObject instances, streamlining JSON serialization and deserialization.

$json = '{"name": "PowerShell", "version": 7}'
$obj = $json | ConvertFrom-Json

Invoke DSC Resources Directly from PowerShell 7

Directly invoking Desired State Configuration (DSC) resources within PowerShell 7 scripts bridges traditional configuration management with modern PowerShell scripting, enhancing automation capabilities.

There ya go! Hope you find something in here that makes coding a bit more fun/easy!