Trouble installing posh-git

I want to install posh-git on laptop but when I try installing w/command "PowerShellGet\Install-Module posh-git -Scope CurrentUser -AllowPrerelease -Force" I get error:

Install-Module : A parameter cannot be found that matches parameter name
'AllowPrerelease'.
At line:1 char:58
+ ... et\Install-Module posh-git -Scope CurrentUser -AllowPrerelease -Force
+                                                   ~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Install-Module], Paramet
   erBindingException
    + FullyQualifiedErrorId : NamedParameterNotFound,Install-Module

Reading the errata at the github site I see it says I need to update my PowerShellGet module w/ "Install-Module PowerShellGet -S cope CurrentUser -Force -AllowClobber" But this gives error :

PackageManagement\Install-Package : The module 'PackageManagement' cannot be
installed or updated because the authenticode signature of the file
'PackageManagement.cat' is not valid.
At C:\Program
Files\WindowsPowerShell\Modules\PowerShellGet\1.0.0.1\PSModule.psm1:1809
char:21
+ ...          $null = PackageManagement\Install-Package @PSBoundParameters
+                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (Microsoft.Power....InstallP
   ackage:InstallPackage) [Install-Package], Exception
    + FullyQualifiedErrorId : InvalidAuthenticodeSignature,ValidateAndGet-Au
   thenticodeSignature,Microsoft.PowerShell.PackageManagement.Cmdlets.Insta
  llPackage

I have googled and tried several ways to update PowerShellGet from v1.0.0.1 which shows on my laptop, all to no avail. Any advice on how to rectify this would be much appreciated.

Solution

The error is specific. You are using a parameter / switch that does not exist by default for modules.

# get function / cmdlet details
(Get-Command -Name Install-Module).Parameters.Keys
<#
Name
InputObject
MinimumVersion
MaximumVersion
RequiredVersion
Repository
Credential
Scope
Proxy
ProxyCredential
AllowClobber
SkipPublisherCheck
Force
Verbose
Debug
ErrorAction
WarningAction
InformationAction
ErrorVariable
WarningVariable
InformationVariable
OutVariable
OutBuffer
PipelineVariable
WhatIf
Confirm
#>
Get-help -Name Install-Module -Examples
Get-help -Name Install-Module -Full
Get-help -Name Install-Module -Online

As per the docs:

Prerelease Versioning Added to PowerShellGet and PowerShell Gallery

Developers have to add this or it's not available for use.

Publishers simply add the prerelease string (ie. the part that comes after “2.0.0”) in the metadata, and the version will be considered prerelease. For example:

@{
   ModuleVersion = '2.0.0'
   #---
      PrivateData = @{
         PSData = @{
            Prerelease = '-alpha'
      }
   }
}

This...

PowerShellGet\Install-Module

… is also not the common way (that I am aware of) regarding how you install a module. You should only need the Install-Module cmdlet, PowerShell already knows the module it comes from and autoloads that, if not already loaded.

Try this...

Find-Module -Name posh-git

Version    Name       Repository           Description
-------    ----       ----------           -----------
0.7.3      posh-git   PSGallery            Provides prompt ...



Find-Module -Name posh-git | 
Save-Module -Path "$env:USERPROFILE\Documents\WindowsPowerShell\Modules" # -WhatIf

What if: Performing the operation "Save Package" on target "'posh-git' to location 'C:\Users\Daniel\Documents\WindowsPowerShell\Modules'".


Install-Module -Name posh-git -Scope CurrentUser -Force