Powershell command to backup a SQL Server DB

if you are running sql server 2008 you have powershell bindings. See this link

SQL Server 2008 powershell has a cmdlet invoke-sqlcmd.

It is possible, there are some pre-requisites you need to have installed (namely the Microsoft SQL Server 2005 Management Objects Collection) and theres quite alot of powersehll code needed to do it, however there are a number of articles out there that have it allready done for you. I have used this method successfully in the past.

You can use ADO.NET from PowerShell to execute a stored proc..

See this example.

There's functions for PowerShell-based SQL Server database backups included in the CodePlex project SQL Server PowerShell Extensions (SQLPSX). Take look at Invoke-SqlBackup or if you want to implement a full backup and maintenance routine take a look at the SQLMaint module.