Emacs indent/unindent current line

Question

I've been using Emacs for a while, and I really miss a good old Geany shortcut - "C-i" and "C-u".

"C-i" indents the whole current line (keeping the mouse cursor where it is), and "C-u" unindents the whole current line.

I found many indenting commands for Emacs, some to indent a region. Basically, what I need is Vim's ">>" and "<<", but keeping the mouse cursor where it is.

My main doubt is, however, how I can indent only the current line.

Any ideas? Thank you in advance!

EDIT Tab adds two spaces, I want to be on any position on the line and add two spaces on the beginning of the line, or remove two spaces from the beginning of the line.

What about ``? Generally programming mods indents current line with ``. — Selman Ulug, Mar 14 '12 at 17:13
Tab adds two spaces, I want to be on any position on the line and add two spaces on the beginning of the line, or remove two spaces from the beginning of the line. I'll add that to the question, sorry. — David Gomes, Mar 14 '12 at 17:43

score 5 · Answer 1 · answered Mar 14 '12 at 17:17

That is the default behavior I have for my TAB key in emacs, which runs the command indent-for-tab-command. From one of the documentation pages:

In programming modes, adds or removes some combination of space and tab characters at the start of the line, in a way that makes sense given the text in the preceding lines. If the region is active and spans multiple lines, all those lines are indented this way. If point was initially within the current line's indentation, it is positioned after that indentation; otherwise, it remains at same point in the newly-indented text. See Program Indent.

Also worth noting is the tab-always-indent variable:

The variable tab-always-indent tweaks the behavior of the (indent-for-tab-command) command. The default value, t, gives the behavior described above. If you change the value to the symbol complete, then first tries to indent the current line, and if the line was already indented, it tries to complete the text at point (see Symbol Completion). If the value is nil, then indents the current line only if point is at the left margin or in the line's indentation; otherwise, it inserts a real tab character.

score 0 · Answer 2 · answered Jul 01 '18 at 06:57

I have this in my init.el:

(defun rofrol/indent-region(numSpaces)
    (progn 
        ; default to start and end of current line
        (setq regionStart (line-beginning-position))
        (setq regionEnd (line-end-position))

        ; if there's a selection, use that instead of the current line
        (when (use-region-p)
            (setq regionStart (region-beginning))
            (setq regionEnd (region-end))
        )

        (save-excursion ; restore the position afterwards            
            (goto-char regionStart) ; go to the start of region
            (setq start (line-beginning-position)) ; save the start of the line
            (goto-char regionEnd) ; go to the end of region
            (setq end (line-end-position)) ; save the end of the line

            (indent-rigidly start end numSpaces) ; indent between start and end
            (setq deactivate-mark nil) ; restore the selected region
        )
    )
)

(defun rofrol/indent-lines(&optional N)
    (interactive "p")
    (indent-rigidly (line-beginning-position)
                    (line-end-position)
                    (* (or N 1) tab-width)))

(defun rofrol/untab-region (&optional N)
    (interactive "p")
    (rofrol/indent-region (* (* (or N 1) tab-width)-1)))

(defun  rofrol/tab-region (N)
    (interactive "p")
    (if (use-region-p)
        (rofrol/indent-region (* (or N 1) tab-width)) ; region was selected, call indent-region
        (rofrol/indent-lines N); else insert spaces as expected
    ))

(global-set-key (kbd "C->") 'rofrol/tab-region)
(global-set-key (kbd "C-<") 'rofrol/untab-region)

Emacs indent/unindent current line

2 Answers2