If your editor supports editorconfig[1], you could set it to not strip newlines for .md files. :)

[1] http://editorconfig.org/

But I want to strip newlines from .md files.

That's why significant end of line whitespace is a terrible design feature. You can't see it. It might get deleted accidentally.

There were some systems back in the DOS/early UNIX era which had significant EOL whitespace. Spaces at the end of a line are still significant following a "\" in shell files. Some early word processors under DOS had significant whitespace at EOL, but tended to display something like a paragraph mark when it mattered.

Python had tab/space trouble at beginnings of lines, but the compiler was finally fixed so that it emits an error if tabs and spaces are mixed in a way which makes indentation visually ambiguous. That was a neat solution to the problem.

Leading tabs in makefiles were a mistake. The author of "make" once wrote that he put that in, and then, the next day, realized it was a bad idea. But he already had a user base of three users and didn't want to change it and break their code.

I thought this idea was dead and buried. Sometimes, they come back.

MD could have been fine if it were the beginning of the line. "Any indentation without a blank line above is BR"

It would make multiple repeated BRs difficult, though, but you probably shouldn't be doing that anyways.

For what it's worth, GitHub Flavored Markdown changes this to be more TeXy: any newline in text renders as a <br>, and you add an extra blank line to denote a paragraph break.

Unfortunately that means that you absolutely need to enable word wrap in your editor, people cat-ing your readme on the shell will see ugly mid-word wraps, etc. Not the end of the world or anything, but somewhat inconvenient.

That sounds like a failure of cat more than a failure of markdown. There isn't a command-line argument for cat to break long-lines at the last whitespace of the line instead of mid-word?

Err, I of course meant "strip trailing whitespace", not "strip newlines", but apparently everyone understood.

I never knew it either.

Intriguing: significant white space on the right-hand side. At least you can see the significant whitespace in Python.

I also have my editor configured to strip trailing whitespace but also to highlight it. People can be very sloppy leaving (insignificant) whitspace lying around in code.