GNU Emacs Manual. Node: Indentation

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Chapter 18: Indentation

This chapter describes the Emacs commands that add, remove, or adjust indentation.


Indent current line ``appropriately'' in a mode-dependent fashion.

C-j Perform RET followed by TAB (newline-and-indent).
M-^ Merge two lines (delete-indentation). This would cancel out the effect of C-j.
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 nonblank 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 many details are different.

Whatever the language, to indent a line, use the TAB command. Each major mode defines this command to perform the sort of indentation appropriate for the particular language. In Lisp mode, TAB aligns the 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.

  • Indentation Commands Various commands and techniques for indentation.
  • Tab Stops You can set arbitrary "tab stops" and then indent to the next tab stop when you want to.
  • Just Spaces You can request indentation using just spaces.
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