Delete old, merged git branches from a remote

delete-merged-git-branches.ps1

# Recipe for deleting old, merged branches from a remote repository

# delete stuff already merged into this branch...
$developBranch = 'develop'
# ...and whose most recent commit is older than this...
$ifOlderThan = [datetime]'06-01-2017'
# ...on this remote
$remote = 'origin'

# Get list of all remote branches already merged into develop
$branches = git branch --merged $developBranch -r | % { $_ -replace '  ','' } | ? { -not ( $_ -like "*HEAD*" ) -and $_ -like "$remote*" }

# Generate a list of {name, date} objects
$times = $branches | % {
  [pscustomobject]@{
    name = $_;
    date = [DateTime](git log -1 '--pretty=format:%cI' $_)
  }
}

# Drop the old, merged branches from the server
$times | ? {
  $_.date.compareTo($ifOlderThan) -eq -1
} | % {
  git push $remote ":$( $_.name -replace "$remote/",'' )"
}