GNU Emacs Manual - Indentation Go to the first , previous , next , last section, table of contents . This chapter describes the Emacs commands that add, remove, or adjust indentation. This would cancel out the effect of C-j .
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.