$x = get-mailpublicfolder | select identity,alias
$x | foreach {$_.alias = $_.alias -replace " - ","-"}
$x | foreach {set-mailpublicfolder $_.identity -alias $_.alias}
$x = get-mailpublicfolder | select identity,alias
#The line below replaces the value in the first quote (which is a space) with a hyphen
$x | foreach {$_.alias = $_.alias -replace " ","-"}
                     $x = get-mailpublicfolder | ? {$_.alias -like "OAB Version *"} | select identity,alias
$x | % {
$newalias = $_.alias -replace " ","-"
set-mailpublicfolder $_.identity -alias $newalias
}
 $x = get-mailpublicfolder | select identity,alias
$x | % {
$newalias = $_.alias -replace " ","-"
` -replace " - ","-"
set-mailpublicfolder $_.identity -alias $newalias
}