File name regular expression

My first use of regular expressions was so easy and such a success I couldn't wait to try my next one. It's proving to be a bit more challenging though.

I am attempting to match a file name pattern to file names read from an IFS directory. What I want is the pattern pfi_nnnn.xml. The files I want will begin with 'pfi_', and end with '.xml'. Currently there are 10 digits in between but I wanted to be able to handle varying numbers. My expression compiles ok but it doesn't match the file names. Doing more research on the web makes me think I'm pretty close but hasn't given me clear direction about the use of the '^' and '$' symbols for matching the beginning and end of a string. In particular, the end of a string. I am attempting to match '.xml' using (.xml)$. My reading has me wondering if $ only matches the last character and not multiple characters. Hopefully someone on the list can help me out with this. I am posting my current expression below.


^(pfi_)[A-Z0-9](.xml)$

Rick

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