Is there a way to execute emacs command on multiple buffers without having to selecting them individually and executing it on each individual buffer.
I usually open multiple files matching a particular regex, e.g. ~/*.py and wish to enable a particular mode, say hs-minor-mode or glasses-mode on each, or say execute C-c # C-M-h on each. Currently I have to select each one of them and do it individually. So is there a hack or a loop to automate the task.
Lets say I mark the buffers from the buffer-list and then run the command for all those marked.
I tried this but after executing the commands in eval-expression I completely lost access to my minibuffer, meaning whenever I typed M-x the minibuffer returned this
unable to access the minibuffer emacs error "Process Menu Mode doesn't support Hideshow Minor Mode"
and I was forced to actually kill the entire emacs process because the C-x C-s wasn't working neither was the End Task.
PS: I have no experience in elisp
You can use ibuffer mode for this (It is part of the default Emacs distribution).
(global-set-key "\C-x\C-b" 'ibuffer) ;; make ibuffer the default
In *Ibuffer* you can mark the required buffers with m and then
execute a form in each with E.
Generally, ibuffer is a lot more flexible then the usual buffer list and I think ibuffer should really be the default buffer-list in Emacs.
If you do this often, you might want to switch those particular modes on every time you enter python mode by attaching them to the mode-hook:
(add-hook 'python-mode-hook 'hs-minor-mode)
(add-hook 'python-mode-hook 'glasses-mode)
I didn't know ibuffer had that feature!
Anyway, for those who are more familiar with dired, here is a command that do the same. Select the files in dired with m or any other more powerful method. Then do, M-xdired-do-command and write a form or a command just as in M-x.
(defun dired-do-command (command)
"Run COMMAND on marked files. Any files not already open will be opened.
After this command has been run, any buffers it's modified will remain
open and unsaved."
(interactive
(list
(let ((print-level nil)
(minibuffer-history-position 0)
(minibuffer-history-sexp-flag (1+ (minibuffer-depth))))
(unwind-protect
(read-from-minibuffer
"Command: " (prin1-to-string (nth 0 command-history))
read-expression-map t
(cons 'command-history 0))
;; If command was added to command-history as a
;; string, get rid of that. We want only
;; evaluable expressions there.
(if (stringp (car command-history))
(setq command-history (cdr command-history)))))))
(dolist (filename (dired-get-marked-files))
(with-current-buffer (find-file-noselect filename)
(if (symbolp command)
(call-interactively command)
(eval command)))))
Related
I'm having a hard time making this emacs -nw work effectively under the terminal mode (emacs -nw).
Some setup information:
The working server is connected via SSH, and emacs is running on the server. Usually I'm connecting using SSH and "emacs -nw" to work on my files.
The emacs config is picked up from: https://hugoheden.wordpress.com/2009/03/08/copypaste-with-emacs-in-terminal/
;; make mouse selection to be emacs region marking
(require 'mouse)
(xterm-mouse-mode t)
(defun track-mouse (e))
(setq mouse-sel-mode t)
;; enable clipboard in emacs
(setq x-select-enable-clipboard t)
;; enable copy/paste between emacs and other apps (terminal version of emacs)
(unless window-system
(when (getenv "DISPLAY")
;; Callback for when user cuts
(defun xsel-cut-function (text &optional push)
;; Insert text to temp-buffer, and "send" content to xsel stdin
(with-temp-buffer
(insert text)
;; I prefer using the "clipboard" selection (the one the
;; typically is used by c-c/c-v) before the primary selection
;; (that uses mouse-select/middle-button-click)
(call-process-region (point-min) (point-max) "xsel" nil 0 nil "--clipboard" "--input")))
;; Call back for when user pastes
(defun xsel-paste-function()
;; Find out what is current selection by xsel. If it is different
;; from the top of the kill-ring (car kill-ring), then return
;; it. Else, nil is returned, so whatever is in the top of the
;; kill-ring will be used.
(let ((xsel-output (shell-command-to-string "xsel --clipboard --output")))
(unless (string= (car kill-ring) xsel-output)
xsel-output )))
;; Attach callbacks to hooks
(setq interprogram-cut-function 'xsel-cut-function)
(setq interprogram-paste-function 'xsel-paste-function)
;; Idea from
;; http://shreevatsa.wordpress.com/2006/10/22/emacs-copypaste-and-x/
;; http://www.mail-archive.com/help-gnu-emacs#gnu.org/msg03577.html
))
The reason to have:
(require 'mouse)
(xterm-mouse-mode t)
(defun track-mouse (e))
(setq mouse-sel-mode t)
is to enable mouse selection over text such that the text region is highlighted just as "C-x SPC" marking the region. Then I can use "M-x w" to copy and "C-x y" to paste text within emacs and between emacs and other apps.
All look perfect except that any operations related to X are REALLY SLOW! My connection to the remote server is smooth -- the latency is usually under 100ms. But to kill one line of text using "C-x k", it takes ~5 seconds! To paste it, it takes another 5 seconds!
When copy/paste is frequent sometimes, this becomes really annoying. I think this is related to the X sever messaging, but not sure if there is good way to fix this.
Any ideas?
Thanks!
This is not an ideal solution per se, but i figured out a way that I feel better than the previous one.
The idea is to get rid of X which causes heavy latency issues, i.e. keep only the following:
;; enable clipboard in emacs
(setq x-select-enable-clipboard t)
The results are:
copy/paste within Emacs is straightforward and fast.
copy from other apps to Emacs: Ctrl+Shift+v
copy from Emacs to other apps: mouse selection is now on X Selection, so right-click and copy shall copy the text into the Selection. Note that 'M-w" now won't copy anything into Selection or system clipboard.
This is again a compromise rather than a solution, but considering the fact that i copy/paste more often than inter-app operations, this is acceptable at the moment.
Still looking forward to a good solution!
You can accomplish this by using a terminal escape code!
There is a unique category of terminal escape codes called "Operating System Controls" (OSC) and one of these sequences (\033]52) is meant for interacting with the system clipboard. The great thing is that your terminal doesn't care where the code came from so it will work in remote sessions as well.
Most terminal emulators support it (iTerm2, OS X Terminal, and I think all Linux terminals besides GNOME). You can test if your terminal supports this sequence by simply running:
$ printf "\033]52;c;$(printf "Hello, world" | base64)\a"
Then paste from your system clipboard. If it pastes "Hello, world" then your terminal supports it!
I have this function in my init.el so when I call yank-to-clipboard Emacs will yank the value from my kill ring into the system clipboard:
(defun yank-to-clipboard ()
"Use ANSI OSC 52 escape sequence to attempt clipboard copy"
(interactive)
(send-string-to-terminal
(format "\033]52;c;%s\a"
(base64-encode-string
(encode-coding-string
(substring-no-properties
(nth 0 kill-ring)) 'utf-8) t))))
As I type this, I stumbled upon an almost-identical script supported by Chromium community: https://chromium.googlesource.com/apps/libapps/+/master/hterm/etc/osc52.el
For those running Emacs inside Tmux:
Tmux consumes the sequence, so you'll need to pipe the sequence to the Tmux active tty for this to work. I have a solution in my blog post here: https://justinchips.medium.com/have-vim-emacs-tmux-use-system-clipboard-4c9d901eef40
To extend on #justinokamoto's answer for use in tmux, it works great and is truly amazing. I haven't debugged it with e.g. tramp or other fancy emacs settings but to get it to work
Follow https://sunaku.github.io/tmux-yank-osc52.html great instructions, modifying your tmux.conf and ~/bin/yank
Make sure terminal access to your clipboard is enabled on your terminal
Then to pull into emacs you can use a function like:
(Caveat emptor, I am very new to elisp. This writes to a temporary file in /tmp/yank)
(defun custom-terminal-yank (&rest args)
(message "-> CLIP")
;; FOR EVIL MODE: UNCOMMENT SO FIRST YANKS TO KILL RING
;; need to yank first, with all those args
;; ;; https://emacs.stackexchange.com/questions/19215/how-to-write-a-transparent-pass-through-function-wrapper
;; (interactive (advice-eval-interactive-spec
;; (cadr (interactive-form #'evil-yank))))
;; (apply #'evil-yank args)
;; https://stackoverflow.com/questions/27764059/emacs-terminal-mode-how-to-copy-and-paste-efficiently
;; https://sunaku.github.io/tmux-yank-osc52.html
(f-write-text (nth 0 kill-ring) 'utf-8 "/tmp/yank")
(send-string-to-terminal (shell-command-to-string "~/bin/yank /tmp/yank"))
)
If anyone else uses evil mode as well (just to make things complicated) you can uncomment those lines and use something like
(define-key evil-visual-state-map "Y" 'jonah-terminal-yank)
So that normal "y" is for normal yanking in visual mode, but "Y" is for cross-clipboard yanking
How to kill an internal process in Emacs? For example I run M-x shell.
I can check running processes with M-x list-processes but how can I kill a process from this list?
There is no default key binding for this; however see pjammer's answer -- list-processes+ includes (among other things) a kill binding on C-k -- and also Joao Tavora's answer -- which provides just a kill binding (for the same key).
event_jr points out in the comments that you can use M-: (kill-process) RET to kill the current buffer's process.
More generally: You can use M-: (kill-process PROCESS) RET, where PROCESS "may be a process, a buffer, or the name of a process or buffer", with those names being as they appear in the output of list-processes. Process names take precedence over buffer names, should you happen to have a conflict; so it's probably best to be in the habit of supplying the process name.
Alternatively, Emacs 23+ has a general system process manager (M-x proced) which is more akin to running top, and which does have a default binding for sending (arbitrary) signals (k). Of course it may be far less obvious in that listing which process you're interested in.
Edit: Better late than never :) The following enables M-x kill-process RET to be used (tested in Emacs 26.1):
;; Enable M-x kill-process (to kill the current buffer's process).
(put 'kill-process 'interactive-form
'(interactive
(let ((proc (get-buffer-process (current-buffer))))
(if (process-live-p proc)
(unless (yes-or-no-p (format "Kill %S? " proc))
(error "Process not killed"))
(error (format "Buffer %s has no process" (buffer-name))))
nil)))
This thread is ancient but here's a very quick hack that works perfectly for me
(define-key process-menu-mode-map (kbd "C-k") 'joaot/delete-process-at-point)
(defun joaot/delete-process-at-point ()
(interactive)
(let ((process (get-text-property (point) 'tabulated-list-id)))
(cond ((and process
(processp process))
(delete-process process)
(revert-buffer))
(t
(error "no process at point!")))))
An alternative way:
You can use M-x eval-expression RET
Then type: (delete-process "<name-of-the-process>") RET
(where "name-of-the-process" was previously obtained from M-x list-processes RET).
Confirm that the process was killed by repeating M-x list-processes RET).
And that's it.
it looks like there is a new mode or add on you can use instead called list process +
If you use counsel you can run M-x counsel-list-processes. You can then type M-o to bring up actions, one of which is kill.
I would like to implement a function that would let me cycle only through directory buffers that are open, and skip files or scratch buffers.
How would I go about that?
Take a look at tabbar mode -- you can define the groups to anything you want (e.g., dired), and cycle between groups with tabbar-backward-group and tabbar-forward-group:
http://www.emacswiki.org/emacs/TabBarMode
tabbar-buffer-list-function can be used to further define whether certain files are displayed (or hidden).
tabbar-buffer-groups is the default group which can be modified with setq to whatever you want. If you want to create alternative methods of grouping, you can use tabbar-buffer-groups-function.
If dired is a group, then you can switch between those buffers by using (setq tabbar-cycle-scope 'tabs) with tabbar-backward and tabbar-forward.
If you'd like to have a go at implementing something,
have a look at Buffer-menu-mode. It's already got a toggle T for
showing only files.
And then it's just a matter to see how it builds the list
and filter it with
(eq major-mode 'dired-mode)
The source is quite small at strangely 665 lines.
I use buffer-stack for this.
I wrote two different functions that use that package: one for switching between dired buffers, and other for switching between buffers of the same mode I am. I use both intensively. This is how I do it:
;; For shorter keybindings
(defmacro command (&rest body)
`(lambda ()
(interactive)
,#body))
(defvar buffer-stack-mode)
(defun buffer-op-by-mode (op &optional mode)
(let ((buffer-stack-filter 'buffer-stack-filter-by-mode)
(buffer-stack-mode (or mode major-mode)))
(funcall op)))
(defun buffer-stack-filter-by-mode (buffer)
(with-current-buffer buffer
(equal major-mode buffer-stack-mode)))
(global-set-key [(meta kp-7)]
(command (buffer-op-by-mode 'buffer-stack-up)))
(global-set-key [(meta kp-9)]
(command (buffer-op-by-mode 'buffer-stack-down)))
(global-set-key [(meta kp-3)]
(command (buffer-op-by-mode 'buffer-stack-down 'dired-mode)))
(global-set-key [(meta kp-1)]
(command (buffer-op-by-mode 'buffer-stack-up 'dired-mode)))
EDIT:
I include the macro I use for command keybindings
Icicles offers a couple ways to do this.
Start in a Dired buffer and do C-0 C-x b TAB
C-x b, then C-x m +, then enter dired-mode (using completion), then TAB
Those give you only Dired buffers as the available candidates, which you can then match by name.
You can cycle among the buffers that match your input, using arrow keys (C-up, C-down). Use RET or C-g to end.
Prefix arg 0 means the candidates are the buffers in the same mode as the current buffer --- hence the first option above.
When completing, C-x C-m + prompts you for a mode and then filters out all candidates whose mode is not the same as or derived from the mode you enter (in this case, dired-mode) --- hence the second option above.
C-x b is bound in Icicle mode to icicle-buffer. If you want to open the buffers in different windows then use C-x 4 b (icicle-buffer-other-window).
See http://www.emacswiki.org/emacs/Icicles_-_Buffer-Name_Input for more info.
In Emacs, I often find myself in a situation where I need to jump back and forth between various source files to various terminals. However, I feel like I do not have a good way to do this efficiently and it's clumsy that you can only open one shell in Emacs (shell, eshell, or term).
Moreover, I need an efficient way of juggle between multiple terminals and source files.
How can I achieve this?
You can have as many terminals and shells open at once as you want. Just use M-x rename-buffer to change the name of an existing *term* or *shell* buffer, and the next time you do M-x term or M-x shell, a brand new buffer will be created. In the case of M-x shell, a prefix argument will cause you to be prompted for the name of the new shell buffer, as offby1 noted.
A few years ago I had a job where I had to regularly log in to various production servers named "host01.foo.com", "host02.foo.com", etc. I wrote a little function like this one to make it easier to manage them all:
(defun ssh-to-host (num)
(interactive "P")
(let* ((buffer-name (format "*host%02d*" num))
(buffer (get-buffer buffer-name)))
(if buffer
(switch-to-buffer buffer)
(term "/bin/bash")
(term-send-string
(get-buffer-process (rename-buffer buffer-name))
(format "ssh host%02d.foo.com\r" num)))))
Then I bound this command to (say) s-h (super H), enabling me to just type M-5 s-h. If I didn't already have a buffer named *host05*, it would start a new terminal emulator buffer, rename it to *host05*, and ssh me into host05.foo.com. If buffer *host05* already existed, it would simply switch me to it. Quite handy!
You can certainly have multiple interactive shells open. Try typing C-u M-x shell RET RET.
Try using MultiTerm to open multiple shells.
You can use Emacs Lisp Screen, which emulates GNU Screen and provides easy key bindings to jump to and between a number of different shells.
I use many methods for incorporating my terminal life into Emacs:
elscreen.el is a life saver, if you have a complicated window layout like gdb or have simply become overwhelmed with clutter you just open a new screen. In your case you could dedicate one screen to terminals.
multi-term.el makes managing terminals a bit easier.
shell-pop.el, a great tool for quick terminal access. shell-pop lets you assign a key to opening and closing a specific shell buffer window, if you've used drop-down terminals like tilda you know how incredibly handy this can be:
Here's and example of my shell-pop configuration, I use the key C-t to pop up an eshell:
(require 'shell-pop)
(shell-pop-set-internal-mode "eshell") ; Or "ansi-term" if you prefer
(shell-pop-set-window-height 60) ; Give shell buffer 60% of window
;; If you use "ansi-term" and want to use C-t
;; (defvar ansi-term-after-hook nil)
;; (add-hook 'ansi-term-after-hook
;; '(lambda ()
;; (define-key term-raw-map (kbd "C-t") 'shell-pop)))
;; (defadvice ansi-term (after ansi-term-after-advice (org))
;; (run-hooks 'ansi-term-after-hook))
;; (ad-activate 'ansi-term)
(global-set-key (kbd "C-t") 'shell-pop)
I usually do an an M-x server-start and then use emacsclient --no-wait to open files. I've aliased that to e with some embellishments so that it's a little more convenient.
I do all my work in a single terminal and just "throw" the files I want to edit into Emacs using e. Inside Emacs, I juggle around using iswitchb and it works just fine. YMMV.
I regularly used 10 or so shells in my old workplace. The secret is you have to rename additional shell buffers. I did this automatically though in my .emacs, creating and naming the shells logically (I had projnameRun and projnameBuild for every project). Worked really well together with anything, making it very easy to refind the right shell (you use the end of the project name combined with either r or b for run/build).
Instead of having several terminal windows in emacs, I spawn a different xterm whenever I need a new terminal. This of course is bearable because I use a very lightweight terminal emulator (urxvt) which starts in under 0.2s.
Then I use my window manager to switch between them and emacs frames. A configurable window manager will have plenty of options to tune to switch between windows (extremely) efficiently. Inside emacs, I use windmove and ido-mode, and have bound to C-tab a function that switches to the last buffer (because I use C-x b in that fashion a lot).
So um, not sure how useful it is to you since it's quite different from your use pattern, but this is what works for me.
I had exactly the same problem some years ago, and found nothing that satisfied me; so I wrote my own "toggle shell" function. It toggles between the current frame or window configuration and a system shell buffer. It can also put the shell into a dedicated frame, and inject a pushd to the current buffer directory.
This is an excerpt from my .emacs:
(defvar --toggle-shell-last-window-conf nil "The last window configuration.")
(defvar --toggle-shell-last-buf nil "The last buffer object in case there's no last window configuration.")
(defvar --toggle-shell-last-frame nil "The frame that was selected when opening a shell buffer.")
(defun --toggle-shell-have-conf ()
(window-configuration-p --toggle-shell-last-window-conf))
(defun --toggle-shell-store-last-conf ()
(setq --toggle-shell-last-buf (current-buffer)
--toggle-shell-last-frame (selected-frame)
--toggle-shell-last-window-conf (current-window-configuration)))
(defun --toggle-shell-restore-last-conf ()
(if (--toggle-shell-have-conf)
(progn (raise-frame --toggle-shell-last-frame)
(set-window-configuration --toggle-shell-last-window-conf))
(let ((bufnam (if (bufferp --toggle-shell-last-buf)
(buffer-name --toggle-shell-last-buf) --toggle-shell-last-buf)))
(if bufnam
(if (get-buffer bufnam) (switch-to-buffer bufnam t)
(message "%s: buffer not available" bufnam))))))
(defun --toggle-shell (&optional display inject-cd)
"Toggles between current buffers and a system shell buffer. With prefix-arg
close the shell.
When DISPLAY is 'vertical splits the shell as vertical window; when 'frame uses
a dedicated frame (default: single window). When INJECT-CD executes a `pushd'
to the working directory of the buffer from which you toggled the shell."
(interactive)
(let* ((shell-buf (get-buffer "*shell*"))
(shell-window ; non-nil when currently displayed
(if shell-buf (get-buffer-window shell-buf t)))
(shell-frame
(if shell-window (window-frame shell-window)))
(in-shell (eq (current-buffer) shell-buf))
(vertical (string= display 'vertical))
(popup-frame (or (string= display 'frame)
(and inject-cd (not (bufferp shell-buf)))
(and (framep shell-frame)
(not (eq shell-frame (selected-frame)))))))
;; With prefix-arg close shell, restore windows. Otherwise (no prefix-arg)
;; toggle shell window; restore windows when called twice in a row, or the
;; current buffer is the shell buffer (`in-shell').
(if current-prefix-arg
(if (bufferp shell-buf)
(progn (message "Exiting shell '%s'" (buffer-name shell-buf))
(kill-buffer shell-buf)
(if in-shell (--toggle-shell-restore-last-conf)))
(error "No shell buffer to kill."))
;; If already in shell-buffer toggle back to stored frame-configuration.
(if (and in-shell (not inject-cd))
(progn
(--toggle-shell-restore-last-conf)
;; Recurse to reopen the shell-buffer in a dedicated frame, or
;; close the dedicated frame and reopen the buffer in a window.
(if (and popup-frame (eq shell-frame (selected-frame)))
(--toggle-shell 'frame inject-cd)
(when (and popup-frame shell-frame)
(delete-frame shell-frame)
(--toggle-shell nil inject-cd))))
;; Not in shell buffer. Warp to it or create new one.
(unless in-shell
(--toggle-shell-store-last-conf))
(if popup-frame
(progn (switch-to-buffer-other-frame (or shell-buf "*shell*"))
(raise-frame
(or shell-frame (window-frame (get-buffer-window "*shell*" t)))))
(if (> (count-windows) 1)
(delete-other-windows)))
;; Finally `cd' into the working directory the current buffer.
(let ((new-shell (not (bufferp shell-buf)))
(new-dir ; `default-directory' of `--toggle-shell-last-buf'
(if --toggle-shell-last-buf
(buffer-local-value 'default-directory --toggle-shell-last-buf))))
;; Open shell, move point to end-of-buffer. The new shell-buffer's
;; `default-directory' will be that of the buffer the shell was
;; launched from.
(when vertical
(if (> (count-windows) 1)
(delete-other-windows))
(split-window-vertically) (other-window 1))
(funcall 'shell)
(when new-shell
(message "New shell %s (%s)" (buffer-name (current-buffer)) new-dir)
(if inject-cd (sit-for 2))) ; wait for prompt
(goto-char (point-max))
;; If on a command-prompt insert and launch a "cd" command (assume no
;; job is running).
(when (and inject-cd new-dir)
(save-excursion
(backward-line-nomark) (end-of-line)
(unless (setq inject-cd (re-search-forward comint-prompt-regexp (point-max) t))
(error "Cannot `pushd', shell is busy")))
(when (and inject-cd)
(let* ((cmd (format
"pushd '%s' %s" (comint-quote-filename new-dir)
(if (buffer-file-name --toggle-shell-last-buf)
(format "# '%s'" (file-name-directory (buffer-file-name --toggle-shell-last-buf)))
""))))
;; `shell-process-cd' set new `default-directory' and set
;; `shell-last-dir' to old. (If the pushd command is
;; successful, a dirs is performed as well; >nul discards this
;; output.)
(shell-process-cd new-dir)
(insert cmd)
(comint-send-input)
(message "%s: cd '%s'" (buffer-name --toggle-shell-last-buf) new-dir))
)
)
)
)
)
)
)
--toggle-shell is the function that does the trick. I bind it to F12:
;; F12 toggle between shell buffer and current window configuration
;; SHIFT-F12 like before, but let shell buffer appear in a dedicated frame
;; ALT-F12 inject a pushd to change to directory of current buffer
;; CTRL-F12 `shell-command'
(global-set-key [(f12)] '--toggle-shell)
(global-set-key [(shift f12)] '(lambda()(interactive)(--toggle-shell 'frame)))
(global-set-key [(meta f12)] '(lambda()(interactive)(--toggle-shell nil t)))
(global-set-key [(meta f10)] '(lambda()(interactive)(--toggle-shell nil t)))
(global-set-key [(control f12)] 'shell-command) ; alias M-!
This is a significant bunch of code to be posted here. But it shall work well.
Semi related - you can quickly run a shell command on selected file with
M+shift+!
It saves a lot of time for smaller commands chmod etc
And maybe my quick pop-up shell also might help you. A quick pop-up shell for emacs
Ecb + eshell will be what you want exactly!
I use vi, but hope this helps. I can open as many terminals as I want by (eg. in Ubuntu 16.04):
ctrl + alt + t
I usually open 2 terminals, and move (position) one terminal to the right by:
ctrl + super + right-arrow
and move the other terminal to the left by:
ctrl + super + left-arrow
so that I have a divided screen by 2 terminals.
If a file is set to read only mode, how do I change it to write mode and vice versa from within Emacs?
M-x read-only-mode
in very old versions of Emacs, the command was:
M-x toggle-read-only
On my Windows box, that amounts to Alt-x to bring up the meta prompt and typing "read-only-mode" to call the correct elisp function.
If you are using the default keyboard bindings,
C-x C-q
(which you read aloud as "Control-X Control-Q") will have the same effect. Remember, however, given that emacs is essentially infinitely re-configurable, your mileage may vary.
Following up from the commentary: you should note that the writeable status of the buffer does not change the writeable permission of the file. If you try to write out to a read only file, you'll see a confirmation message. However, if you own the file, you can write out your changes without changing the permissions on the file.
This is very convenient if you'd like to make a quick change to a file without having to go through the multiple steps of add write permission, write out changes, remove write permission. I tend to forget that last step, leaving potentially critical files open for accidental changes later on.
Be sure you're not confusing 'file' with 'buffer'. You can set buffers to read-only and back again with C-x C-q (toggle-read-only). If you have permission to read, but not write, a file, the buffer you get when you visit the file (C-x C-f or find-file) will be put in read-only mode automatically. If you want to change the permissions on a file in the file system, perhaps start with dired on the directory that contains the file. Documentation for dired can be found in info; C-h i (emacs)dired RET.
What I found is M-x set-file-modes filename mode
It worked at my Windows Vista box.
For example: M-x set-file-modes <RET> ReadOnlyFile.txt <RET> 0666
As mentioned up there by somebody else: M-x toggle-read-only would work.
However, this is now deprecated and M-x read-only-mode is the current way to do it, that it is set to C-x C-q keybinding.
CTRL + X + CTRL + Q
If only the buffer (and not the file) is read-only, you can use toggle-read-only, which is usually bound to C-x C-q.
If the file itself is read-only, however, you may find the following function useful:
(defun set-buffer-file-writable ()
"Make the file shown in the current buffer writable.
Make the buffer writable as well."
(interactive)
(unix-output "chmod" "+w" (buffer-file-name))
(toggle-read-only nil)
(message (trim-right '(?\n) (unix-output "ls" "-l" (buffer-file-name)))))
The function depends on unix-output and trim-right:
(defun unix-output (command &rest args)
"Run a unix command and, if it returns 0, return the output as a string.
Otherwise, signal an error. The error message is the first line of the output."
(let ((output-buffer (generate-new-buffer "*stdout*")))
(unwind-protect
(let ((return-value (apply 'call-process command nil
output-buffer nil args)))
(set-buffer output-buffer)
(save-excursion
(unless (= return-value 0)
(goto-char (point-min))
(end-of-line)
(if (= (point-min) (point))
(error "Command failed: %s%s" command
(with-output-to-string
(dolist (arg args)
(princ " ")
(princ arg))))
(error "%s" (buffer-substring-no-properties (point-min)
(point)))))
(buffer-substring-no-properties (point-min) (point-max))))
(kill-buffer output-buffer))))
(defun trim-right (bag string &optional start end)
(setq bag (if (eq bag t) '(?\ ?\n ?\t ?\v ?\r ?\f) bag)
start (or start 0)
end (or end (length string)))
(while (and (> end 0)
(member (aref string (1- end)) bag))
(decf end))
(substring string start end))
Place the functions in your ~/.emacs.el, evaluate them (or restart emacs). You can then make the file in the current buffer writable with M-x set-buffer-file-writable.
If you are looking at a directory of files (dired), then you can use Shift + M on a filename and enter the modespec, the same attributes used in the chmod command.
M modespec <RET>
See the other useful commands on files in a directory listing at
http://www.gnu.org/s/libtool/manual/emacs/Operating-on-Files.html
I tried out Vebjorn Ljosa's solution, and it turned out that at least in my Emacs (22.3.1) there isn't such function as 'trim-right', which is used for removing an useless newline at the end of chmod output.
Removing the call to 'trim-right' helped, but made the status row "bounce" because of the extra newline.
C-x C-q is useless. Because your also need the permission to save a file.
I use Spacemacs. It gives me a convenient function to solve this question. The code is following.
(defun spacemacs/sudo-edit (&optional arg)
(interactive "p")
(if (or arg (not buffer-file-name))
(find-file (concat "/sudo:root#localhost:" (ido-read-file-name "File: ")))
(find-alternate-file (concat "/sudo:root#localhost:" buffer-file-name))))
I call spacemacs/sudo-edit to open a file in emacs and input my password, I can change the file without read-only mode.
You can write a new function like spacemacs/sudo-edit.