How are tabs treated differently in different systems?

Question

To maintain portability, tab characters must not be used in indentation, since different systems treat tabs differently.

Anyone knows?

Answer 1

Where is this quote from? Does it talk about indentation in code, or in WYSIWYG documents, or in output of console programs that must be parsable?

As for code indentation, tabs can have same size as any number of spaces (usually 2, 4 or 8). So if you mix spaces and tabs, once you open same file in different editor with different tab settings you would see broken indentation. The solution to that is not to use spaces for indentation (opposite of what your quote says).

Another advantage of all-tabs indentation is ability to adjust visual size of tabs (some people like 'em bigger).

Python has this insane whitespace scoping mechanism that would cause inconsistent indentation to break code.