How can I load changes to my .emacs without rebooting Emacs? [duplicate] - configuration

How can I get Emacs to reload all my definitions that I have updated in .emacs without restarting Emacs?

You can use the command load-file (M-x load-file, and then press Return twice to accept the default filename, which is the current file being edited).
You can also just move the point to the end of any sexp and press C-x, C-e to execute just that sexp. Usually it's not necessary to reload the whole file if you're just changing a line or two.

There is the very convenient
M-x eval-buffer
It immediately evaluates all code in the buffer. It's the quickest method if your .emacs file is idempotent.

You can usually just re-evaluate the changed region. Mark the region of ~/.emacs that you've changed, and then use M-x eval-region RET. This is often safer than re-evaluating the entire file since it's easy to write a .emacs file that doesn't work quite right after being loaded twice.

If you've got your .emacs file open in the currently active buffer:
M-x eval-buffer

Solution
M-: (load user-init-file)
Notes
you type it in Eval: prompt (including the parentheses)
user-init-file is a variable holding the ~/.emacs value (pointing to the configuration file path) by default
(load) is shorter, older, and non-interactive version of (load-file); it is not an Emacs command (to be typed in M-x), but a mere Elisp function
Conclusion
M-: > M-x

M-x load-file
~/.emacs

Others already answered your question as stated, but I find that I usually want to execute the lines that I just wrote.
For that, Ctrl + Alt + X in the Elisp part works just fine.

The following should do it...
M-x load-file

I suggest that you don't do this, initially. Instead, start a new Emacs session and test whatever changes you made to see if they work correctly. The reason to do it this way is to avoid leaving you in a state where you have an inoperable .emacs file, which fails to load or fails to load cleanly. If you do all of your editing in the original session, and all of your testing in a new session, you'll always have something reliable to comment out offending code.
When you are finally happy with your changes, then go ahead and use one of the other answers to reload. My personal preference is to eval just the section you've added/changed, and to do that just highlight the region of added/changed code and call M-x eval-region. Doing that minimizes the code that's evaluated, minimizing any unintentional side-effects, as luapyad points out.

Keyboard shortcut:
(defun reload-init-file ()
(interactive)
(load-file user-init-file))
(global-set-key (kbd "C-c C-l") 'reload-init-file) ; Reload .emacs file

C-x C-e ;; current line
M-x eval-region ;; region
M-x eval-buffer ;; whole buffer
M-x load-file ~/.emacs.d/init.el

Define it in your init file and call by M-x reload-user-init-file
(defun reload-user-init-file()
(interactive)
(load-file user-init-file))

I'm currently on Ubuntu 15.04 (Vivid Vervet); I like to define a key for this.
[M-insert] translates to Alt + Ins on my keyboard.
Put this in your .emacs file:
(global-set-key [M-insert] '(lambda() (interactive) (load-file "~/.emacs")))

Besides commands like M-x eval-buffer or M-x load-file, you can restart a fresh Emacs instance from the command line:
emacs -q --load "init.el"
Usage example: Company backends in GNU Emacs

Here is a quick and easy way to quick test your config. You can also use C-x C-e at the end of specific lisp to execute certain function individually.
C-x C-e runs the command eval-last-sexp (found in global-map), which
is an interactive compiled Lisp function.
It is bound to C-x C-e.
(eval-last-sexp EVAL-LAST-SEXP-ARG-INTERNAL)
Evaluate sexp before point; print value in the echo area.
Interactively, with prefix argument, print output into current buffer.
Normally, this function truncates long output according to the value
of the variables ‘eval-expression-print-length’ and
‘eval-expression-print-level’. With a prefix argument of zero,
however, there is no such truncation. Such a prefix argument also
causes integers to be printed in several additional formats (octal,
hexadecimal, and character).
If ‘eval-expression-debug-on-error’ is non-nil, which is the default,
this command arranges for all errors to enter the debugger.

Although M-x eval-buffer will work, you may run into problems with toggles and other similar things. A better approach might be to "mark" or highlight what’s new in your .emacs file (or even scratch buffer if you're just messing around) and then M-x eval-region.

You can set a key binding for Emacs like this:
;; Reload Emacs configuration
(defun reload-init-file ()
(interactive)
(load-file "~/.emacs"))
(global-set-key (kbd "C-c r") 'reload-init-file)

If you happen to have a shell opened inside Emacs, you can also do:
. ~/.emacs
It may save a few key strokes.

Related

Is there a way to undefine a function in emacs lisp?

I have a macro that creates function. It creates interactive functions based on current opened buffer. However, it starts to flood the M-x after a long running section. Is there a way to make a function invalid?
You can use fmakunbound:
(fmakunbound 'my-boring-function)

Loading tcl extension from tclsh

I have a C extension to Tcl where command mytest is defined. The extension is compiled correctly (I am on Linux, extension is *.so). For example, I can start tclsh and use it like this:
$ tclsh
% load /path/extension.so
% mytest abc
...
But, if I create a file myscript.tcl with the following content:
load /path/extension.so
mytest abc
then I get error:
$ tclsh myscript.tcl
invalid command name "mytest"
while executing
"mytest abc"
(file "myscript.tcl" line 2)
I am using bash on Ubuntu 14.04. Tcl 8.6.
EDIT 1: My question/problem is that I want to use tclsh with a script as an argument - this script should properly load extensions in such a way that mytest and other implemented functions are working without error.
EDIT 2: Uhh, If I use command "source myscript.tcl" inside tcl shell the result is the same. If I use absolute path for myscript.tcl the error is still the same --- "load" executes without warning but I am not sure about it because I get invalid command name "mytest". Maybe the problem is with scope, but it is working correctly when tclsh is used interactively.
If you are using the full path of the extension library in both cases, that part should work identically. It probably is doing though; if it couldn't load it, it would generate an error (which might or might not be helpful, as some of the ways that things fail give very little information; Tcl reports what it has got, but that's sometimes not enough, as it is dependent on the OS to tell it some things). Instead, the problem is probably elsewhere.
The main difference between interactive use and scripted use is that in interactive use, the unknown command will expand unknown command names to Tcl commands that the thing you typed is an unambiguous prefix of. This is convenient, but when converting to a script, you should always use the full command name. OK, not the full full command name — you mostly don't want or need the :: namespace on the front — but without abbreviation, so don't use lappe for lappend. (In interactive use, Tcl will also exec things as external programs without requiring you to type the exec explicitly; again, that's turned off in scripts as it is rather fragile.)
Could it be that this is what is going on? You can check by setting the global variable tcl_interactive to 0 before typing in your code (I recommend using cut-n-paste for that typing, so that you know exactly what is going in). If that fails, it's the interactive-mode helpfulness that is tripping you up. Check what commands you might have as an expansion for a prefix with info commands (after the load, of course):
info commands mytest*
If that just reports mytest, my theory is wrong. (Well, if it does that and the length of that string is 6; there could theoretically be extra invisible characters have been put on the command name, which would be legal Tcl but very nasty and DON'T DO THAT!)

How to disable a modified tclsh interpreter interactive mode?

Run tclsh command without any tcl file, the interpreter will go into interactive mode.
Can I simply disable this feature by modifying the tclsh source code ?
I can't imagine why you would want to bother doing this, given that supplying any script file will turn off interactive mode. The script you supply will have full access to the additional arguments passed in (a list in the global argv variable) and the standard IO channels (stdin, stdout and stderr). It can exit when it is done. Literally anything you want can be done at that point; you've just got to write a script to do it.
If you're including Tcl in your own program, the behaviour of tclsh is implemented in the C function Tcl_Main. If you never call that — instead just using Tcl_FindExecutable, Tcl_CreateInterp and Tcl_Eval/Tcl_EvalFile — then you never get any of that interactive behaviour. While theoretically you could modify the Tcl source itself to do what you want — it's all open source — why would you bother when you could just not call that code in the first place?

Is there Octave's equivalent for iPython's "!"

For example,
!vim
in iPython opens vim. Is there such a thing in Octave?
The following might work system("vim");
If you want the interactivity of calling something inside of Octave and interactivity with it directly try exec("vim") instead.
See Controlling Subprocesses for more examples.
Otherwise you can either combine calls to system, fork and exec or extend octave with Python/iPython or C++.
If you only want to run another process then , the already suggested system() or exec() should work.
However, if you plan on using this to simply open up a text editor and edit an Octave file, set the value of EDITOR with EDITOR ("vim") (you can add this to your .octaverc file) and then use edit (foo) to open up the foo function on the text editor.

Watch file(s) for modifications algorithm

I was simply wondering how file watching algorithms are implemented. For instance, let's say I want to apply a filter (i.e., search/replace a string) to a file every time it is modified, what technique should I use? Obviously, I could run an infinite loop that would check every file in a directory for modifications, but it might not be very efficient. Is there any way to get notified directly by the OS instead? For the sake of demonstration, let's assume a *nix OS and whatever language (C/Ruby/Python/Java/etc.).
Linux has inotify, and judging from the wikipedia links, Windows has something similar called 'Directory Management'. Without something like inotify, you can only poll..
In Linux there is the Inotify subsystem which will alert you to file modification.
JavaSE 7 will have File Change Notification as part of NIO.2 updates.
There are wrappers to inotify that make it easy to use from high-level languages. For example, in ruby you can do the following with rb-inotify:
notifier = INotify::Notifier.new
# tell it what to watch
notifier.watch("path/to/foo.txt", :modify) {puts "foo.txt was modified!"}
notifier.watch("path/to/bar", :moved_to, :create) do |event|
puts "#{event.name} is now in path/to/bar!"
end
There's also pyinotify but I was unable to come up with an example as concise as the above.