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Comment by xg15 | Hacker News Reader

What always confused me on Windows is how shells (e.g. CMD) fit into all of this. You can use pipes, variables, semicolon delimiters etc inside a line, which have to be parsed by the shell before launching any process - and those interact with quoting!

So does that mean the shell first parses a line using its own quoting rules, then launches the processes which parse the line again, possibly using a different set of quoting rules?

This sounds plainly insane.

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Yes the shell interprets it first. `cmd.exe` does very little processing and mostly passes on the literal string. But what it does do can be confusing (e.g. `^` is an escape character which is annoying if you were trying to pass in a regex).

In powershell you can use `--%` to pass a literal string as the command line. This is useful for applications that don't use the standard C/C++ parsing rules.

See: https://docs.microsoft.com/en-us/powershell/module/microsoft...

Thank you very much for pointing out --%. I often find it incredibly hard to find what I'm looking for from Microsoft's voluminous tutorial-style Powershell docs.

Yep, which leads to things like the following not creating out.txt (in cmd.exe)

  prog.exe "abc \" def" > out.txt

IIRC Batch interprets ^ escapes unless it's double quoted - so, yes.

It also has a different idea of what’s actually double-quoted: it ignores backslashes completely. (Well, the Microsoft C runtime and SHELL32.DLL also have different ideas in that regard, as mentioned in the links in the post, but CMD.EXE’s different different idea is ... more different. I still don’t understand whetehr SHELL32.DLL and pre-2008 C runtime are the same or not. An MSDN blog post discussing this is—concisely if not in detail—here: https://docs.microsoft.com/en-gb/archive/blogs/twistylittlep...; I think I came upon it by following links from the head post but I can’t seem to recover the path.)

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