One folder is called '_Customer Template.' This folder is used to provision new customers. In our example below we have a document library called 'Customers." Inside, we have a folder for each customer.
The $i expands/reads the variable, replacing it with the current number being handled.SharePoint is a great document repository, but surprisingly working with documents in SharePoint may not always be intuitive.
This iterates through every number in the sequence 1000–1100 and assigns the current number to the variable named i, a common shorthand for "index". What you want is a for loop, as suggested in your other post: If you wanted to copy directories, you add the -r option to the command. For completeness, the errors you got were because, being a potentially expensive operation, cp doesn't copy directories by default. So what it tried to do was copy the file filename and directories 1, 2, 3, and 4 into directory 5 (which isn't what you wanted to do). When executed, the program cp attempts to copy all the arguments, except the last one, into the final argument.
When you say mkdir, the shell expands that into cp filename 1 2 3 4 5. It may be worthwhile to find a beginner shell tutorial online to familiarize yourself with the basic utilities and syntax.