about_PSReadLine

Artikkeli
09/17/2024

Short Description

PSReadLine provides an improved command-line editing experience in the PowerShell console.

There have been many updates to PSReadLine since the version that ships in Windows PowerShell 5.1.

v2.3.5 first shipped in PowerShell 7.4.2 and 7.5.0-preview.3
v2.3.4 first shipped in PowerShell 7.4.0-rc.1
v2.2.6 first shipped in PowerShell 7.3.0
v2.1.0 first shipped in PowerShell 7.2.5
v2.0.4 first shipped in PowerShell 7.0.11
v2.0.0 ships in Windows PowerShell 5.1

For more information about version differences, see about_PSReadLine_Release_Notes.

Long Description

The current version of PSReadLine can be installed and used on Windows PowerShell 5.1 and newer. For some features, you need to be running PowerShell 7.2 or higher.

PSReadLine provides a powerful command-line editing experience for the PowerShell console. It provides:

Syntax coloring of the command line
A visual indication of syntax errors
A better multi-line experience (both editing and history)
Customizable key bindings
Cmd and Emacs modes
Many configuration options
Bash style completion (optional in Cmd mode, default in Emacs mode)
Emacs yank/kill-ring
PowerShell token based "word" movement and deletion
Predictive IntelliSense
Dynamic display of Help in the console without losing your place on the command line

PSReadLine requires PowerShell 5.1, or newer. PSReadLine works with the default Windows console host, Windows Terminal, and Visual Studio Code. It doesn't work in the Windows PowerShell ISE.

PSReadLine can be installed from the PowerShell Gallery. To install PSReadLine in a supported version of PowerShell run the following command.

Install-Module -Name PSReadLine -AllowClobber -Force

Note

Beginning with PowerShell 7.0, PowerShell skips autoloading PSReadLine on Windows if a screen reader program is detected. Currently, PSReadLine doesn't work well with the screen readers. The default rendering and formatting of PowerShell 7.0 on Windows works properly. You can manually load the module if necessary.

Predictive IntelliSense

Predictive IntelliSense is an addition to the concept of tab completion that assists the user in successfully completing commands. It enables users to discover, edit, and execute full commands based on matching predictions from the user's history and additional domain specific plugins.

Enable Predictive IntelliSense

Predictive IntelliSense is disabled by default. To enable predictions, just run the following command:

Set-PSReadLineOption -PredictionSource History

The PredictionSource parameter can also accept plugins for domain specific and custom requirements.

To disable Predictive IntelliSense, just run:

Set-PSReadLineOption -PredictionSource None

Custom Key Bindings

PSReadLine supports custom key bindings using the Set-PSReadLineKeyHandler cmdlet. Most custom key bindings call one of the bindable functions, for example

Set-PSReadLineKeyHandler -Key UpArrow -Function HistorySearchBackward

You can bind a ScriptBlock to a key. The ScriptBlock can do pretty much anything you want. Some useful examples include

edit the command line
opening a new window (for example, help)
change directories without changing the command line

The ScriptBlock receives two arguments:

$key - A [ConsoleKeyInfo] object that is the key that triggered the custom binding. If you bind the same ScriptBlock to multiple keys and need to perform different actions depending on the key, you can check $key. Many custom bindings ignore this argument.
$arg - An arbitrary argument. Most often, this would be an integer argument that the user passes from the key bindings DigitArgument. If your binding doesn't accept arguments, it's reasonable to ignore this argument.

Let's take a look at an example that adds a command line to history without executing it. This is useful when you realize you forgot to do something, but don't want to re-enter the command line you've already entered.

$parameters = @{
    Key = 'Alt+w'
    BriefDescription = 'SaveInHistory'
    LongDescription = 'Save current line in history but do not execute'
    ScriptBlock = {
      param($key, $arg)   # The arguments are ignored in this example

      # GetBufferState gives us the command line (with the cursor position)
      $line = $null
      $cursor = $null
      [Microsoft.PowerShell.PSConsoleReadLine]::GetBufferState([ref]$line,
        [ref]$cursor)

      # AddToHistory saves the line in history, but does not execute it.
      [Microsoft.PowerShell.PSConsoleReadLine]::AddToHistory($line)

      # RevertLine is like pressing Escape.
      [Microsoft.PowerShell.PSConsoleReadLine]::RevertLine()
  }
}
Set-PSReadLineKeyHandler @parameters

You can see many more examples in the file SamplePSReadLineProfile.ps1, which is installed in the PSReadLine module folder.

Most key bindings use some helper functions for editing the command line. Those APIs are documented in about_PSReadLine_Functions.

Notes

Command History

PSReadLine maintains a history file containing all the commands and data you've entered from the command line. The history files are a file named $($host.Name)_history.txt. On Windows systems the history file is stored at $env:APPDATA\Microsoft\Windows\PowerShell\PSReadLine. On non-Windows systems, the history files are stored at $env:XDG_DATA_HOME/powershell/PSReadLine or $env:HOME/.local/share/powershell/PSReadLine.

The history can contain sensitive data including passwords. PSReadLine attempts to filter out sensitive information. Any command lines containing the following strings aren't written to the history file.

password
asplaintext
token
apikey
secret

PSReadLine 2.2.0 improves the filtering of sensitive data

Uses the PowerShell Abstract Syntax Tree (AST) of the parsed command line to look for sensitive data.
Uses an allowlist of safe cmdlets from the SecretManagement module to allow those commands to be added to the history. The allowlist contains:
- Get-Secret
- Get-SecretInfo
- Get-SecretVault
- Register-SecretVault
- Remove-Secret
- Set-SecretInfo
- Set-SecretVaultDefault
- Test-SecretVault
- Unlock-SecretVault
- Unregister-SecretVault

For example, the following commands are allowed to be written to the history file:

Get-Secret PSGalleryApiKey -AsPlainText # Get-Secret is in the allowlist
$token = Get-Secret -Name github-token -Vault MySecret
[MyType]::CallRestAPI($token, $url, $args)
$template -f $token

The following commands aren't being written to the history file:

$token = 'abcd' # Assign expr-value to sensitive variable name.
Set-Secret abc $mySecret # Set-Secret is not in the allowlist.
ConvertTo-SecureString stringValue -AsPlainText # '-AsPlainText' is an alert.
Invoke-WebRequest -Token xxx # Expr-value as argument to '-Token'.
Get-ResultFromTwo -Secret1 (Get-Secret -Name blah -AsPlainText) -Secret2 sdv87ysdfayf798hfasd8f7ha # '-Secret2' has expr-value argument.

If there are other commands you don't want written to the history files, you can use the AddToHistoryHandler parameter of the Set-PSReadLineOption cmdlet. For an example of how to use AddToHistoryHandler, see Example 7 of Set-PSReadLineOption.

PSReadLine 2.3.4 improves the filtering of sensitive data

Improved the default sensitive history scrubbing to allow the history to contain safe property access.

When the sensitive string is part of a property access:

If this member access operation isn't part of an assignment, then we consider it safe
Otherwise, if the right-hand side is a pipeline or a variable, we also consider it safe

For example, the following use cases are considered safe and can be saved to the history.

$a.Secret = Get-Secret -Name github-token -Vault MySecret
$a.Secret = $secret
$a.Password.Secret | Set-Value
$token = (Get-AzAccessToken -ResourceUrl 'https://app.contoso.com').Token

The release also improved the sensitive history scrubbing to allow retrieving token using the az, gcloud, and kubectl command-line tools.