How can I control the indentation of a line in a plain text file?
fundamental-mode, when you begin to type a line (call it Line A) after a previous line by hitting return, the line will automatically inherit the indent of the previous line.
When I manually delete the automated indent, and want 3 tabs as indent instead by hitting tab three times, it seems that the second tab is converted to spaces, because I saw the cursor didn't jump by tab but by a character when I hit the second tab.
When I create another line (call it Line B) and remove any automated indent of it, if I hit just one tab key, it will jump to the same indent as that of Line A, and Line A has an indent more than just one tab.
C-q TAB. I'm not sure if Emacs has a special mode for this kind of indenting, but there's a good chance it has, giving Google a spin might be worthwhile.