19 Indentation

TAB

Indent current line “appropriately” in a mode-dependent fashion.

LFD

Perform RET followed by TAB (newline-and-indent).

M-^

Merge two lines (delete-indentation). This would cancel out the effect of LFD.

C-M-o

Split line at point; text on the line after point becomes a new line indented to the same column that it now starts in (split-line).

M-m

Move (forward or back) to the first non-blank character on the current line (back-to-indentation).

C-M-\

Indent several lines to same column (indent-region).

C-x TAB

Shift block of lines rigidly right or left (indent-rigidly).

M-i

Indent from point to the next prespecified tab stop column (tab-to-tab-stop).

M-x indent-relative

Indent from point to under an indentation point in the previous line.

Most programming languages have some indentation convention. For Lisp code, lines are indented according to their nesting in parentheses. The same general idea is used for C code, though details differ.

Use the TAB command to indent a line whatever the language. Each major mode defines this command to perform indentation appropriate for the particular language. In Lisp mode, TAB aligns a line according to its depth in parentheses. No matter where in the line you are when you type TAB, it aligns the line as a whole. In C mode, TAB implements a subtle and sophisticated indentation style that knows about many aspects of C syntax.

In Text mode, TAB runs the command tab-to-tab-stop, which indents to the next tab stop column. You can set the tab stops with M-x edit-tab-stops.