Delete local branches whose remote tracking branches were gone.

DeleteLocalBranchesWhoseRemoteTrackingBranchesWereGone.ps1

git fetch origin -np

$BranchesToDelete = New-Object -TypeName System.Collections.Generic.List[string]
$BranchList = (git branch -vv)
foreach ($Branch in $BranchList) {
    if ($Branch.ToString().Contains(": gone]")) {
        $BranchesToDelete.Add($Branch.ToString().TrimStart().Split(' ')[0])
    }
}

if ($BranchesToDelete.Count -eq 0) {
    "No local branch needs to be deleted."
    return;
}

Write-Host "The following local branch(es) will be deleted:" -ForegroundColor Yellow
foreach ($BranchName in $BranchesToDelete) {
    Write-Host ("`t" + $BranchName) -ForegroundColor Red
}

$Confirmation = Read-Host "Do you want to delete local branches above? (Y/n)"

# the -eq 'y' is case-insensitive, so it's also true if $Confirmation is 'Y'
if (($Confirmation -eq "y") -or ($Confirmation -eq "")) {
    foreach ($BranchName in $BranchesToDelete) {
        git branch -D $BranchName
    }

    Write-Host "Done." -ForegroundColor Green
}
else {
    "No branch was deleted."
}