A PowerShell script to create a new gist on Github.

New-GithubGist.ps1

#requires -version 4.0

Function New-GitHubGist {

[cmdletbinding(SupportsShouldProcess,DefaultParameterSetName = "Content")]
Param(
[Parameter(Position = 0, Mandatory, HelpMessage = "What is the name for your gist?",ValueFromPipelineByPropertyName)]
[ValidateNotNullorEmpty()]
[string]$Name,

[Parameter(ParameterSetName="path",Mandatory,ValueFromPipelineByPropertyName)]
[ValidateNotNullorEmpty()]
[Alias("pspath")]
[string]$Path,

[Parameter(ParameterSetName="Content",Mandatory)]
[ValidateNotNullorEmpty()]
[string[]]$Content,

[string]$Description,

[Alias("token")]
[ValidateNotNullorEmpty()]
[string]$UserToken = $gitToken,

[switch]$Private,
[switch]$Passthru
)

Begin {
    Write-Verbose "[BEGIN  ] Starting: $($MyInvocation.Mycommand)"  

    #create the header
$head = @{
Authorization = 'Basic ' + $UserToken
}
    #define API uri
    $base = "https://api.github.com"

} #begin

Process {
    #display PSBoundparameters formatted nicely for Verbose output  
    [string]$pb = ($PSBoundParameters | Format-Table -AutoSize | Out-String).TrimEnd()
    Write-Verbose "[PROCESS] PSBoundparameters: `n$($pb.split("`n").Foreach({"$("`t"*2)$_"}) | Out-String) `n" 

    #json section names must be lowercase
    #format content as a string
    
    switch ($pscmdlet.ParameterSetName) {
    "path" {
        $gistContent = Get-Content -Path $Path | Out-String
    }
    "content" {
        $gistContent = $Content | Out-String
    }
    } #close Switch

    $data = @{
        files = @{$Name = @{content = $gistContent}}
        description = $Description
        public = (-Not ($Private -as [boolean]))
    } | Convertto-Json

    Write-Verbose ($data| out-string)
    Write-Verbose "[PROCESS] Posting to $base/gists"
    
    If ($pscmdlet.ShouldProcess("$name [$description]")) {
        
        #parameters to splat to Invoke-Restmethod
        $invokeParams = @{
            Method = 'Post'
            Uri = "$base/gists" 
            Headers = $head 
            Body = $data 
            ContentType = 'application/json'
        }

        $r = Invoke-Restmethod @invokeParams

    if ($Passthru) {
        Write-Verbose "[PROCESS] Writing a result to the pipeline"
        $r | Select @{Name="Url";Expression = {$_.html_url}},
        Description,Public,
        @{Name = "Created";Expression = {$_.created_at -as [datetime]}}
    } 
    } #should process

} #process

End {
    Write-Verbose "[END    ] Ending: $($MyInvocation.Mycommand)"
} #end

} #end function