It doesn’t work everywhere. For example tab completion in cmd.exe doesn’t work for a path containing forward slashes (even when quoted), because forward slash is the prefix character for command-line options.
right but that's a cmd.exe thing, not a Windows thing.
Windows supports it, CMD doesn't. programs that you run from a CMD prompt support other options flag syntaxes, so it's just a cmd.exe feature.
CMD.exe is its own thing with its own backwards compatibility requirements and the case could be made that cmd.exe is "Windows" as much as anything else is, so I get it.
The point is, you can’t just blindly use forward-slash as a file system path separator everywhere on Windows. It’s not on equal footing with backslash in that respect.
That's incorrect. You're confusing totally separate issues by examining specific pieces of software with product specific bugs. This isn't a valid way to examine the issue: by this metric, spaces aren't supported on unix because many programs choke on them.
In fact, you can use forward slashes across the entire file API on Windows. That's the point.
I'm viewing this from the end user's perspective. They can use backslashes everywhere as a path separator, but they can't use forward slashes everywhere. In that sense, forward slashes are in practice a second-class citizen on Windows. The canonical path syntax is and will remain with backslashes.
I'd qualify that as "almost no non-programmers know". Forward slashes are so useful in languages that use \ as an escape sequence that most programmers do know this.
