PowerProcess

This module provides a faster replacement for PowerShell & and Start-Process.

Motive

The default implementation of the PowerShell error stream allocates lots of objects and it's very slow if you need to process the redirect error stream as strings, it also processes line by line with has a high burden on the pipeline.

Another important problem is that the default implementation until PowerShell 7.1.3 internally uses Arguments instead of ArgumentList besides being called ArgumentList, it is a [string], which is unfortunate because of historical reasons.

Improvements

• Added support for buffering output and error streams.
• It's not possible to call the shell by mistake.
• Support for the new VT terminals [WIP].
• Correct treatment of argument lists by the direct use of System.Diagnostics.Process.
• Possibility of merging output and error at the source.

Install

Available in PSGallery: https://www.powershellgallery.com/packages/PowerProcess

Install-Module -Name PowerProcess

Usage

NAME
    Invoke-ProcessFast

SYNTAX
    Invoke-ProcessFast [-FilePath] <string> [[-ArgumentList] <string[]>] [-WorkingDirectory <string>] [-PassThru]
    [-DontRedirectOutputs] [-MergeStandardErrorToOutput] [-WrapOutputStream] [-Wait] [-InputObject <string>]
    [-OutputBuffer <int>] [-WhatIf] [-Confirm] [<CommonParameters>]

    Invoke-ProcessFast [-Credential <pscredential>] [-LoadUserProfile] [-PassThru] [-DontRedirectOutputs]
    [-MergeStandardErrorToOutput] [-WrapOutputStream] [-Wait] [-UseNewEnvironment] [-InputObject <string>]
    [-OutputBuffer <int>] [-WhatIf] [-Confirm] [<CommonParameters>]


ALIASES
    None


REMARKS
    None


PS C:\Users\LuizMonad\Desktop\PowerShellProcess\PowerProcess\bin\Debug\net5.0> get-help Invoke-ProcessFast -full

NAME
    Invoke-ProcessFast

SYNTAX
    Invoke-ProcessFast [-FilePath] <string> [[-ArgumentList] <string[]>] [-WorkingDirectory <string>] [-PassThru]
    [-DontRedirectOutputs] [-MergeStandardErrorToOutput] [-WrapOutputStream] [-Wait] [-InputObject <string>]
    [-OutputBuffer <int>] [-WhatIf] [-Confirm] [<CommonParameters>]

    Invoke-ProcessFast [-Credential <pscredential>] [-LoadUserProfile] [-PassThru] [-DontRedirectOutputs]
    [-MergeStandardErrorToOutput] [-WrapOutputStream] [-Wait] [-UseNewEnvironment] [-InputObject <string>]
    [-OutputBuffer <int>] [-WhatIf] [-Confirm] [<CommonParameters>]


PARAMETERS
    -ArgumentList <string[]>

        Required?                    false
        Position?                    1
        Accept pipeline input?       false
        Parameter set name           ScriptBlock
        Aliases                      Args
        Dynamic?                     false
        Accept wildcard characters?  false

    -Confirm

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      cf
        Dynamic?                     false
        Accept wildcard characters?  false

    -Credential <pscredential>

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           WinEnv
        Aliases                      RunAs
        Dynamic?                     false
        Accept wildcard characters?  false

    -DontRedirectOutputs

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      NoRedir
        Dynamic?                     false
        Accept wildcard characters?  false

    -FilePath <string>

        Required?                    true
        Position?                    0
        Accept pipeline input?       false
        Parameter set name           ScriptBlock
        Aliases                      PSPath, Path
        Dynamic?                     false
        Accept wildcard characters?  false

    -InputObject <string>

        Required?                    false
        Position?                    Named
        Accept pipeline input?       true (ByValue)
        Parameter set name           (All)
        Aliases                      None
        Dynamic?                     false
        Accept wildcard characters?  false

    -LoadUserProfile

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           WinEnv
        Aliases                      Lup
        Dynamic?                     false
        Accept wildcard characters?  false

    -MergeStandardErrorToOutput

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      Merge
        Dynamic?                     false
        Accept wildcard characters?  false

    -OutputBuffer <int>

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      None
        Dynamic?                     false
        Accept wildcard characters?  false

    -PassThru

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      None
        Dynamic?                     false
        Accept wildcard characters?  false

    -UseNewEnvironment

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           WinEnv
        Aliases                      None
        Dynamic?                     false
        Accept wildcard characters?  false

    -Wait

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      None
        Dynamic?                     false
        Accept wildcard characters?  false

    -WhatIf

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      wi
        Dynamic?                     false
        Accept wildcard characters?  false

    -WorkingDirectory <string>

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           ScriptBlock
        Aliases                      None
        Dynamic?                     false
        Accept wildcard characters?  false

    -WrapOutputStream

        Required?                    false
        Position?                    Named
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      Obj
        Dynamic?                     false
        Accept wildcard characters?  false

    <CommonParameters>
        This cmdlet supports the common parameters: Verbose, Debug,
        ErrorAction, ErrorVariable, WarningAction, WarningVariable,
        OutBuffer, PipelineVariable, and OutVariable. For more information, see
        about_CommonParameters (https://go.microsoft.com/fwlink/?LinkID=113216).


INPUTS
    System.String


OUTPUTS
    System.Diagnostics.Process
  or
    System.String


ALIASES
    None


REMARKS
    None

EXAMPLES

Example 1: Start a process redirecting all of its streams.

This example starts a process that will redirect its error stream to output as a string.

Invoke-ProcessFast -FilePath pwsh -ArgumentList @('-noprofile', '-command', '0; 1; 2; 3') -MergeStandardErrorToOutput

Example 2: Start a process redirecting all of its streams as objects.

This example starts a process that will redirect its streams to output objects so you can differentiate which stream it came from.

Invoke-ProcessFast -FilePath pwsh -ArgumentList @('-noprofile', '-command', '0; 1; 2; 3') -MergeStandardErrorToOutput -WrapOutputStream

Example 3: Start a process while without buffering its output in a list.

This example starts a process that won't buffer the processing in a list, this is an optimization that shouldn't matter for ForEach-Object or sending to the Host or Transcript or using foreach, but in some cases, you may want to disable it or change the default value, to disable this feature, set the buffer to 1, the default value is 256.

Invoke-ProcessFast -FilePath pwsh -ArgumentList @('-noprofile', '-command', '0; 1; 2; 3') -MergeStandardErrorToOutput -WrapOutputStream -OutputBuffer 1

PARAMETERS

-ArgumentList

Specifies parameters or parameter values to use when this cmdlet starts the process. Arguments can be accepted as a single string with the arguments separated by spaces, or as an array of strings separated by commas. The cmdlet joins the array into a single string with each element of the array separated by a single space.

The outer quotes of the PowerShell strings are not included when the ArgumentList values are passed to the new process. If parameters or parameter values contain a space or quotes, they must be surrounded with escaped double quotes. For more information, see about_Quoting_Rules.

Type: System.String[]
Parameter Sets: (All)
Aliases: Args

Required: False
Position: 1
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-PassThru

Returns a process object for each process that the cmdlet started. By default, this cmdlet does not generate any output.

Type: System.Management.Automation.SwitchParameter
Parameter Sets: (All)
Aliases:

Required: False
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-Wait

Indicates that this cmdlet waits for the specified process and its descendants to complete before accepting more input. This parameter suppresses the command prompt or retains the window until the processes finish.

Type: System.Management.Automation.SwitchParameter
Parameter Sets: (All)
Aliases:

Required: False
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-WorkingDirectory

Specifies the location where the new process should start. The default is the location of the executable file or document that is started. Wildcards are not supported. The path name must not contain characters that would be interpreted as wildcards.

Type: System.String
Parameter Sets: (All)
Aliases:

Required: False
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-Confirm

Prompts you for confirmation before running the cmdlet.

Type: System.Management.Automation.SwitchParameter
Parameter Sets: (All)
Aliases: cf

Required: False
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-WhatIf

Shows what would happen if the cmdlet runs. The cmdlet will not be executed.

This parameter was introduced in PowerShell 6.0.

Type: System.Management.Automation.SwitchParameter
Parameter Sets: (All)
Aliases: wi

Required: False
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

CommonParameters

This cmdlet supports the common parameters: -Debug, -ErrorAction, -ErrorVariable, -InformationAction, -InformationVariable, -OutVariable, -OutBuffer, -PipelineVariable, -Verbose, -WarningAction, and -WarningVariable. For more information, see about_CommonParameters.

INPUTS

None

You can pipe input to this cmdlet, it will be converted to a string and sent synchronously to the process.

OUTPUTS

None, System.Diagnostics.Process

This cmdlet generates a System.Diagnostics.Process object, if you specify the PassThru parameter. Otherwise, this cmdlet does not return any output.

NOTES

• When using the Wait parameter, Invoke-ProcessFast waits for the created process to exit before returning control. This is different than the behavior of the Start-Process cmdlet, which waits for the process tree (windows job).

• This cmdlet is implemented using the Start method of the System.Diagnostics.Process class. For more information about this method, see Process.Start Method.

• On Windows, when you use UseNewEnvironment, the new process starts only containing the default environment variables defined for the Machine scope. This has the side effect that the $env:USERNAME is set to SYSTEM. None of the variables from the User scope are included.

Related Projects and scripts

This provides a way to return all the output as an error when the process ExitCode is non-zero. But it saves output and error as temporary files, so we lose streaming, which is no good. It also doesn't solve the problem of escaping arguments.

Adam Bertram blog post

Invoke-Process on the gallery

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This person provides a better implementation of the Invoke-Process than Adam's one because it uses BeginOutputReadLine and BeginErrorReadLine instead of temporary files. But it also suffers from the same problems, its a bit better in that it directly uses System.Diagnostics.Process

guitarrapc_tech blog post

Invoke-Process on their utils GitHub repo

---

This also suffers from the same problems, it's a bit simpler implementation worth mentioning

Relevant discussion

Invoke-NativeCommand mentioned

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And the final implementation I found was in a citation from mklement0 in one of the discussions on GitHub issues. It solves the problem with the arguments, it kind of plays well with streams, and it does the right thing in relation to the ordering of error and input, but it doesn't play well with the powershell pipeline, it redirects the entire buffer to a variable, which is not that nice if you want realtime processing as the process generates the output.

Invoke-ExternalCommand