SS64 Forum

Simon Sheppard

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Registered: 27 Aug 2005

Posts: 1,130

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Reserved filenames

@Foone brings up an interesting point about reserved filenames on Windows:

It is 2018 and this error message is a mistake from 1974. This limitation, which is still found in the very latest Windows 10, dates back to BEFORE STAR WARS. This bug is as old as Watergate.
... https://twitter.com/Foone/status/1058676834940776450

I've documented these limitations at the bottom of the filenames page here: https://ss64.com/nt/syntax-filenames.html

Something I hadn't realised before is that creating a file like NUL.txt is only "not recommended" rather than explicitly reserved, so operations like COPY CON NUL.txt or COPY demo.txt NUL.txt will succeed and return errorlevel = 0 but no file will get generated.
I think that failure to raise an error could be called a bug.