[icebraining]

The shell by default ignores spaces, you have to specifically force it to acknowledge them by enclosing the name in quotation marks or escaping with a backslash. In that situation, a command line tool should do what it's told, not disobey a direct command. Leave the rubber padded tools for the GUI land.

[harrytuttle]

Rubber padded I do not expect. Retarded I also do not expect.

Explain the validity of:

   mkdir " "
   mkdir "  "
   mkdir "   "

?

It at least violates the principle of least surprise

[icebraining]

Validity? It's a string like any other. It's not mkdir's job to second-guess what I tell it to do.

And I don't see how it violated such principle. You tell it to create a file with spaces - you even emphasized them with quotes -, and you're surprise it did so?

[harrytuttle]

It is merely an illustration. The reality is stuff like that occasionally does happen when you use variables and parse results from other commands.