Tabletop/Simulated failover - the disaster recovery procedures are implemented on a limited scale. Participants engage in role-playing to ensure comprehension and realism.
Parallel recovery using a non-production test environment - the disaster recovery procedures are implemented in a non-production environment. VMs work especially well for this kind of test. The production environment remains unaffected.

Scripts are written using a shell language. The shell is the server's command-line environment.
The default shell for Linux is bash. Windows has two shells: cmd.exe and PowerShell, although Microsoft emphasizes PowerShell. As a general rule, a script written for one shell, such as PowerShell, will not be understood by another shell, such as bash. The system must have the appropriate shell installed to process the script.
Bash script -- a script written in bash language that contains commands, variables, constructs, and other components. Bash scripts are almost always written for Linux systems.
VBS script -- a script written in the VBScript language. Microsoft has deprecated VBScript, but there have been many VBScript scripts written over the years. VBScript scripts are almost always written for Windows systems.