Windows PowerShell is a very powerful and extremely useful tool in today’s IT. But when it comes to complex PowerShell scripts to automate tasks to make your job a little easier, handling errors properly will go a long way. Error handling shouldn’t just be limited to big and complex scripts, short scripts benefit a lot also if unexpected events are handled properly so things don’t go south.<\/p>\n\n\n\n
There are two types of errors you should worry about in PowerShell — Terminating<\/strong> and Non-terminating<\/strong> errors. Terminating errors are serious errors during execution that brings the script to a complete stop. Some examples of this are non-existent cmdlets, syntax errors or other fatal errors. Non-terminating errors, on the other hand, are not so serious errors that allow execution to continue despite failures. Examples of this are file not found errors or permission issues. Non-terminating errors cannot be caught by default but you can treat them as terminating errors to catch and do something about them. You can also catch specific exceptions in which case you would like to perform specific actions, but you will have to know the name of the exceptions to catch them individually (no examples are provided because these are not common).<\/p>\n\n\n\n The After a Try, Catch and Finally Blocks<\/h2>\n\n\n\n
Try<\/code> block defines a section of a script to be monitored for errors. \u00a0That means, if an error occurs within the Try<\/code> block, it is first saved to the $Error<\/code> automatic variable. \u00a0PowerShell will then search for a Catch<\/code> block that handles the error properly. \u00a0If a matching Catch<\/code> block is not found, PowerShell will continue to search for it in the parent scope.<\/p>\n\n\n\nCatch<\/code> block completes or if no matching Catch<\/code> block or Trap statement is found, it continues to the Finally<\/code> block (if used). \u00a0Use the Finally<\/code> block to free resources used by a script after the Try<\/code> and Catch<\/code> blocks. \u00a0The Finally<\/code> block runs whether the script inside the Try<\/code> block fails or not. \u00a0It also runs if CTRL+C<\/code> is used to stop the script or if an Exit<\/code> keyword stops the script from within a Catch<\/code> block.<\/p>