The following are examples of different SharePoint PowerShell commands you can use to back up and restore various components of your SharePoint environment.
A complete farm backup followed by a restore:
Back up and restore a service application:
Back up and restore farm configuration information only:
Back up and restore your SharePoint content databases:
Back up and restore a site collection:
Export and import a subsite, list, or library:
See also example of performing a SharePoint 2010 Farm Backup and Restore using STSADM.