Querying Exchange quota limits in Powershell

Get-mailbox | where {$_.UseDatabaseQuotaDefaults -ne $true} 

Get-MailboxDatabase | Get-MailboxStatistics | Where-Object {$_.StorageLimitStatus -match 'BelowLimit|IssueWarning|ProhibitSend|MailboxDisabled'} 

Get-mailbox | get-mailboxstatistics | sort-object totalitemsize –descending | ft displayname,totalitemsize

Get-PublicFolder -Recurse -ResultSize Unlimited  | Get-PublicFolderStatistics -Server <exchange> | Select FolderPath, ItemCount, TotalAssociatedItemSize, TotalDeletedItemSize, TotalItemSize | fl Get-Mailbox -ResultSize Unlimited | Get-MailboxStatistics | Sort-Object TotalItemSize -Descending | Select-Object DisplayName,StorageLimitStatus,TotalItemSize -First 100  | Sort-Object TotalItemSize

Set-Mailbox <mailbox> -UseDatabaseQuotaDefaults $false -IssueWarningQuota 8GB -ProhibitSendQuota 8.5GB

Get-PublicFolder "\" -Recurse -resultsize unlimited| Get-PublicFolderStatistics -Server <server> | Select FolderPath, ItemCount, TotalAssociatedItemSize, TotalDeletedItemSize, TotalItemSize | fl