Gets the content of a gist which you can then save as a file: .\Get-GistFile.ps1 gist_id > filename.ext

Get-GistFile.ps1

param([Parameter(Mandatory)]$Id)

$response = Invoke-WebRequest https://api.github.com/gists/$Id
$gist = $response.Content | ConvertFrom-Json

$gist.files | gm -MemberType NoteProperty | select -First 1 | % {
    $file = $gist.files."$($_.Name)"
    $file.content

    Write-Verbose "filename: $($file.filename)"    
    Write-Verbose "language: $($file.language)"
    Write-Verbose "size: $($file.size)"
}

Write-Verbose "created: $([DateTime]$gist.created_at)"
Write-Verbose "updated: $([DateTime]$gist.updated_at)"
Write-Verbose "public: $($gist.public)"
Write-Verbose "url: $($gist.html_url)"
Write-Verbose "comments: $($gist.comments)"