Indention and tabs in fundamental mode

Question

How can I control the indentation of a line in a plain text file?

In 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.

Answer 1

First of all, are you really editing in fundamental-mode? If you're talking about a plain text file, are you sure you're not in text-mode? You can check with M-: major-mode.

In general, have a look at the manual node on "Indentation".

tab runs indent-for-tab-command in fundamental-mode. The first part of its docstring reads:

Indent the current line or region, or insert a tab, as appropriate. This function either inserts a tab, or indents the current line, or performs symbol completion, depending on tab-always-indent.

You can control the tab stops via tab-stop-list:

List of tab stop positions used by tab-to-tab-stop. This should be a list of integers, ordered from smallest to largest.

If you'd prefer all of your tabs to be converted to spaces, you can turn off indent-tabs-mode with (setq-default indent-tabs-mode nil).

If you'd like to prevent enter from auto-indenting, have a look at the threads for How to disable auto-indentation of new lines? and Emacs version 24.4: New obnoxious loss of indentation on hitting RETURN. Short version: either turn off electric-indent-mode or bind enter to newline rather than newline-and-indent.