I'm currently using the terminal Terminator,
and i got a bash function
set_title() { printf '\e]2;%s\a' "$*"; }
wich permit me to set the terminator window title
So I would want to know if it's possible to execute this specific shell command (like this):
set_title ##filename
on each opening (or re-opening) of the said file in emacs?
(btw english is not my native language, please be indulgent!)
If you mean that you're running the non-GUI Emacs inside bash inside Terminator and you want Terminator's title to reflect the current file in Emacs, then the fact that bash sits in between is of no use to you: Emacs is in control here.
But you can define an Elisp function that will do the same job as your set_title:
(defun my-set-title (title)
(send-string-to-terminal (format "\e]2;%s\a" title)))
And then you could use it via find-file-hook:
(add-hook 'find-file-hook (lambda () (my-set-title buffer-file-name)))
Note that this will set the terminal's title to the last file Emacs visits, so if you switch back to a previous file-buffer via C-x C-b, the title won't be updated to reflect the current buffer's file name. If you want to do that, you'd need something more like:
(defvar my-last-file nil)
(defun my-keep-file-title ()
(when (and buffer-file-name
(not (equal buffer-file-name my-last-file)))
(setq my-last-file buffer-file-name)
(my-set-title buffer-file-name)))
(add-hook 'post-command-hook #'my-keep-file-title)
As suggested by #Dan, you can do
(add-hook find-file-hook
(lambda ()
(when (string= buffer-file-name "my-file")
(shell-command "printf ...."))))
to call printf when you open "my-file".
However, if what you want is to set the frame title (emacs calls "frame" what window managers call "window"),
you should be setting frame-title-format, e.g.:
(setq frame-title-format
'(buffer-file-name "%b - %f" ; File buffer
(dired-directory dired-directory ; Dired buffer
(revert-buffer-function "%b" ; Buffer Menu
("%b - Dir: " default-directory)))) ; Plain buffer
icon-title-format "%b")
Related
In previous emacs, "M-x shell" new a shell buffer in current windows.
but recently, I update my emacs to GNU Emacs 26.0.50.2. "M-x shell" new a shell buffer in the other windows. I search google and could not find answer.
does anybody know how to prevent this behavior.
Add this line in your .emacs file:
(push (cons "\\*shell\\*" display-buffer--same-window-action) display-buffer-alist)
This fixed it for me. I'm using eMacs 25.2 (9.0) on a Mac, and was getting really annoyed by the shell opening up in another frame, or even a new frame when there was only one.
This is the source where I got this answer from.
Unless you're customizing the names of your shell buffers, this should be all you need:
(add-to-list 'display-buffer-alist
`(,(regexp-quote "*shell") display-buffer-same-window))
To handle all shell buffers, whatever their names, you can use this advice:
(defun shell-same-window-advice (orig-fn &optional buffer)
"Advice to make `shell' reuse the current window.
Intended as :around advice."
(let* ((buffer-regexp
(regexp-quote
(cond ((bufferp buffer) (buffer-name buffer))
((stringp buffer) buffer)
(:else "*shell*"))))
(display-buffer-alist
(cons `(,buffer-regexp display-buffer-same-window)
display-buffer-alist)))
(funcall orig-fn buffer)))
(advice-add 'shell :around #'shell-same-window-advice)
The reason is that shell uses (pop-to-buffer buffer) instead of (switch-to-buffer buffer). I don't know how to advise the function, so I can't give you an appropriate answer. However if you only want shell to work the way you want you can simply add the whole function in your config.
Maybe somebody else can replace the function with an advice. I would be interested in that solution.
(defun shell (&optional buffer)
"Run an inferior shell, with I/O through BUFFER (which defaults to `*shell*').
Interactively, a prefix arg means to prompt for BUFFER.
If `default-directory' is a remote file name, it is also prompted
to change if called with a prefix arg.
If BUFFER exists but shell process is not running, make new shell.
If BUFFER exists and shell process is running, just switch to BUFFER.
Program used comes from variable `explicit-shell-file-name',
or (if that is nil) from the ESHELL environment variable,
or (if that is nil) from `shell-file-name'.
If a file `~/.emacs_SHELLNAME' exists, or `~/.emacs.d/init_SHELLNAME.sh',
it is given as initial input (but this may be lost, due to a timing
error, if the shell discards input when it starts up).
The buffer is put in Shell mode, giving commands for sending input
and controlling the subjobs of the shell. See `shell-mode'.
See also the variable `shell-prompt-pattern'.
To specify a coding system for converting non-ASCII characters
in the input and output to the shell, use \\[universal-coding-system-argument]
before \\[shell]. You can also specify this with \\[set-buffer-process-coding-system]
in the shell buffer, after you start the shell.
The default comes from `process-coding-system-alist' and
`default-process-coding-system'.
The shell file name (sans directories) is used to make a symbol name
such as `explicit-csh-args'. If that symbol is a variable,
its value is used as a list of arguments when invoking the shell.
Otherwise, one argument `-i' is passed to the shell.
\(Type \\[describe-mode] in the shell buffer for a list of commands.)"
(interactive
(list
(and current-prefix-arg
(prog1
(read-buffer "Shell buffer: "
;; If the current buffer is an inactive
;; shell buffer, use it as the default.
(if (and (eq major-mode 'shell-mode)
(null (get-buffer-process (current-buffer))))
(buffer-name)
(generate-new-buffer-name "*shell*")))
(if (file-remote-p default-directory)
;; It must be possible to declare a local default-directory.
;; FIXME: This can't be right: it changes the default-directory
;; of the current-buffer rather than of the *shell* buffer.
(setq default-directory
(expand-file-name
(read-directory-name
"Default directory: " default-directory default-directory
t nil))))))))
(setq buffer (if (or buffer (not (derived-mode-p 'shell-mode))
(comint-check-proc (current-buffer)))
(get-buffer-create (or buffer "*shell*"))
;; If the current buffer is a dead shell buffer, use it.
(current-buffer)))
;; On remote hosts, the local `shell-file-name' might be useless.
(if (and (called-interactively-p 'any)
(file-remote-p default-directory)
(null explicit-shell-file-name)
(null (getenv "ESHELL")))
(with-current-buffer buffer
(set (make-local-variable 'explicit-shell-file-name)
(file-remote-p
(expand-file-name
(read-file-name
"Remote shell path: " default-directory shell-file-name
t shell-file-name))
'localname))))
;; The buffer's window must be correctly set when we call comint (so
;; that comint sets the COLUMNS env var properly).
(switch-to-buffer buffer)
(unless (comint-check-proc buffer)
(let* ((prog (or explicit-shell-file-name
(getenv "ESHELL") shell-file-name))
(name (file-name-nondirectory prog))
(startfile (concat "~/.emacs_" name))
(xargs-name (intern-soft (concat "explicit-" name "-args"))))
(unless (file-exists-p startfile)
(setq startfile (concat user-emacs-directory "init_" name ".sh")))
(apply 'make-comint-in-buffer "shell" buffer prog
(if (file-exists-p startfile) startfile)
(if (and xargs-name (boundp xargs-name))
(symbol-value xargs-name)
'("-i")))
(shell-mode)))
buffer)
I have cscope built-in in emacs.
When ever I change the code using emacs. The code change causes cscope to not behave the way I want it to.
eg.
Due to code change If I want to jump to the function definition. cscope does not take me to the definition of the func, instead it takes me to some other line.
Please tell if there is a way to rebuild cscope without closing the emacs window.
You will need https://github.com/dkogan/xcscope.el
and configuration :
(defun my-c-mode-common-hook ()
(require 'xcscope)
(cscope-setup)
(setq cscope-initial-directory "path to the cscope directory"))
(add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
and then
C-c s L (or M-x cscope-create-list-of-files-to-index)
C-c s I (or M-x cscope-index-files) => build or rebuild
Hope this help
I use the following function to build/rebuild cscope database:
(require 'xcscope)
(cscope-setup)
(setq cscope-option-use-inverted-index t)
(defadvice cscope-bury-buffer (after cscope-bury-buffer activate)
"Kill the *cscope* window after hitting q or Q instead of leaving it open."
(delete-window))
(defun cscope-create-database (top-directory)
"Create cscope* files in one step containing, do this before using cscope:
1. C-c s L
2. C-c s I
3. C-c s a
"
(interactive "DCreate cscope* database files in directory: ")
(progn
(cscope-create-list-of-files-to-index top-directory)
(cscope-index-files top-directory)
(setq cscope-initial-directory top-directory)
(sit-for 2)
(delete-windows-on "*cscope-indexing-buffer*")
(kill-buffer "*cscope-indexing-buffer*")
))
(bind-keys*
("C-c s r" . cscope-create-database))
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.
I need to get the full path of the file that I'm editing with emacs.
Is there a function for that?
If not, what would be the elisp function for getting that?
How can I copy the result (path name) to a clipboard so that I can reuse it?
I'm using Mac OS X and Aqumacs.
(setq filepath (get-fullpath-current-file)) ???
(copy-to-clipboard 'filepath) ???
ADDED
(defun show-file-name ()
"Show the full path file name in the minibuffer."
(interactive)
(message (buffer-file-name))
(kill-new (file-truename buffer-file-name))
)
(global-set-key "\C-cz" 'show-file-name)
Combining the two answers that I got, I could get what I want. Thanks for the answers. And some more questions.
What's for (file-truename)?
Can I copy the path name to System(OS)'s clipboard, not the kill ring so that I can use the info with the other apps?
It's the built-in function buffer-file-name that gives you the full path of your file.
The best thing to do is to have your emacs window to always show your system-name and the full path of the buffer you're currently editing :
(setq frame-title-format
(list (format "%s %%S: %%j " (system-name))
'(buffer-file-name "%f" (dired-directory dired-directory "%b"))))
You can also do something like this :
(defun show-file-name ()
"Show the full path file name in the minibuffer."
(interactive)
(message (buffer-file-name)))
(global-set-key [C-f1] 'show-file-name) ; Or any other key you want
To borrow from Jérôme Radix's answer, if you just want to quickly see the file path of the current buffer, you can do M-: buffer-file-name.
Alternately, type (buffer-file-name) in the buffer somewhere and run C-x C-e on the closing parenthesis (this will work in any mode, not just lisp-mode).
My trick is to do a C-x C-f like to open a file, it wil prefill the minibuff with the current file path, C-g to quit. Faster than M-: buffer-file-name but far far uglier than any other methods.
The direct implementation of what you want is:
(defun copy-full-path-to-kill-ring ()
"copy buffer's full path to kill ring"
(interactive)
(when buffer-file-name
(kill-new (file-truename buffer-file-name))))
That said, I find it incredibly useful to be able to get the full path of what is in the minibuffer, and this is what I use:
(define-key minibuffer-local-completion-map "\C-r" 'resolve-sym-link)
(defun resolve-sym-link ()
"Try to resolve symbolic links into true paths."
(interactive)
(beginning-of-line)
(let* ((file (buffer-substring (point)
(save-excursion (end-of-line) (point))))
(file-dir (file-name-directory file))
(file-true-dir (file-truename file-dir))
(file-name (file-name-nondirectory file)))
(delete-region (point) (save-excursion (end-of-line) (point)))
(insert (concat file-true-dir file-name))))
And then if I want it in the clipboard, I just kill the line (C-a C-k). But we could easily copy the truename to the clipboard in the above command, just change the last line to be:
(insert (kill-new (concat file-true-dir file-name)))))
The new part is the call to 'kill-new which puts the string in the kill ring.
No need for extra function, just
M-! pwd
C-x C-b shows a list of buffers and the file path for each buffer where applicable.
C-x C-d, also callable via M-x list-directory, will show you the directory for your current file, and you only need to hit the "Enter" key to clear the minibuffer. Additional details are available here.
I have the following code already in use for a long time.
It copies the full file path to the kill ring when I press the middle mouse button on the buffer name in the mode-line. It copies just the buffer name to the kill-ring when I press shift-mouse-2 on the buffer-name in the mode-line.
(defun copy-buffer-file-name (event &optional bufName)
"Copy buffer file name to kill ring.
If no file is associated with buffer just get buffer name.
"
(interactive "eP")
(save-selected-window
(message "bufName: %S" bufName)
(select-window (posn-window (event-start event)))
(let ((name (or (unless bufName (buffer-file-name)) (buffer-name))))
(message "Saved file name \"%s\" in killring." name)
(kill-new name)
name)))
(define-key mode-line-buffer-identification-keymap [mode-line mouse-2] 'copy-buffer-file-name)
(define-key mode-line-buffer-identification-keymap [mode-line S-mouse-2] '(lambda (e) (interactive "e") (copy-buffer-file-name e 't)))
C-u C-x C-b lists buffers currently visiting files.
Can I copy the path name to System(OS)'s clipboard, not the kill ring so that I can use the info with the other apps?
You can if you shell out to something like xclip (Linux), pbcopy (Mac), putclip (Cygwin).
I personally use wrapper scripts c and p for copy and paste respectively, the first reading from standard input, the latter writing to standard output. That way, this works on all my development platforms:
(shell-command (format "echo '%s' | c" buffer-file-name))
I find this more reliable and configurable than using the Emacs clipboard support. For example, my c command copies the input to all 3 clipboards on Linux (primary, secondary, clipboard), so I can paste with either Ctrl-V or middle click.
The simplest way and would be
(buffer-name)<(C-x)(C-e)> for the file name to appear in the echo area
(buffer-name)<(C-u)(C-x)(C-e)> would print the location <here>
Borrowing from Trey Jackson
I came up with this:
(defun buffer-kill-path ()
"copy buffer's full path to kill ring"
(interactive)
(kill-new (buffer-file-name)))
You can find more information on site
copy-buffer-file-name-as-kill from [0] does exactly what you need I think. It also has the option to copy just directory name, or just file name.
[0] http://www.emacswiki.org/emacs/download/buffer-extension.el
To do what the title says (show the current file path in the minibuffer) you can do this:
M-x buffer-file-name
To permanently show it in the mode-line, you can use this:
(setq-default mode-line-buffer-identification
(list 'buffer-file-name
(propertized-buffer-identification "%12f")
(propertized-buffer-identification "%12b")))
Or this (color + abbrev) :
(setq-default mode-line-buffer-identification
'((:eval
(list (propertize (abbreviate-file-name
(expand-file-name buffer-file-name))
'face 'font-lock-string-face)))))
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.