Opening an already-open file with GNU Emacs - emacs

Suppose that the file A.txt is already opened with GNU-emacs, but I don't notice it, so I try opening it (again) with
emacs A.txt
Instead of just showing the already-open window it opens a second one!
(This is of course annoying, since I will end up with 2 conflicting versions.)
How can I avoid this (under ubuntu) ?

Command emacs starts a new instance of the application.
What you are looking for is emacsclient which connects to an existing emacs instance and tells it to edit the file.
You need to start the server first though.

Related

My .emacs.el file is not loading, how can I get it to load? [duplicate]

I tried looking for the .emacs file for my Windows installation for Emacs, but I could not find it. Does it have the same filename under Windows as in Unix?
Do I have to create it myself? If so, under what specific directory does it go?
Copy and pasted from the Emacs FAQ, http://www.gnu.org/software/emacs/windows/:
Where do I put my init file?
On Windows, the .emacs file may be called _emacs for backward compatibility with DOS and FAT filesystems where filenames could not start with a dot. Some users prefer to continue using such a name, because Windows Explorer cannot create a file with a name starting with a dot, even though the filesystem and most other programs can handle it. In Emacs 22 and later, the init file may also be called .emacs.d/init.el. Many of the other files that are created by Lisp packages are now stored in the .emacs.d directory too, so this keeps all your Emacs related files in one place.
All the files mentioned above should go in your HOME directory. The HOME directory is determined by following the steps below:
If the environment variable HOME is set, use the directory it indicates.
If the registry entry HKCU\SOFTWARE\GNU\Emacs\HOME is set, use the directory it indicates.
If the registry entry HKLM\SOFTWARE\GNU\Emacs\HOME is set, use the directory it indicates. Not recommended, as it results in users sharing the same HOME directory.
If C:\.emacs exists, then use C:/. This is for backward compatibility, as previous versions defaulted to C:/ if HOME was not set.
Use the user's AppData directory, usually a directory called Application Data under the user's profile directory, the location of which varies according to Windows version and whether the computer is part of a domain.
Within Emacs, ~ at the beginning of a file name is expanded to your HOME directory, so you can always find your .emacs file with C-x C-f ~/.emacs.
There's further information at HOME and Startup Directories on MS-Windows.
It should be stored in the variable user-init-file. Use C-H v user-init-file RET to check. You can also open it directly by using M-x eval-expression RET (find-file user-init-file) RET
Open the file like this in Emacs for Windows:
C-x C-f ~/.emacs
More information in the Emacs Wiki
On my Vista box it's in C:\Users\<USER>\AppData\Roaming\
Note that it may NOT be enough to just type Ctrl-x Ctrl-f ~/.emacs and create the file.
It may be that your Emacs application uses a different place to store your init file, and if so, then creating the file ~/.emacs simply creates a useless file which your Emacs application ignores.
Also, you may want to do more than just access the .emacs init file, but you may want to know where it is, i.e., its pathname.
To get at this there are two methods:
Easy way: type Ctrl + H V user-init-file Return
Slightly trickier way:
You can find out where your system is storing its own .emacs file by:
Click options and scroll down to "Set Default Font..."
Change the font setting and click okay
On the options menu, go down to "Save Options"
When the options are saved, the system saves its .emacs file,
and you can read the file path in the minibuffer at the bottom of the Emacs screen
In Windows 7 put your init.el file in C:\Users\user-name\AppData\Roaming\.emacs.d\, where user-name is your user/login folder.
Take care so your init.el file won't be named init.el.txt. This is something Windows does if you create your file with some editor like Notepad.
On versions of Emacs on Windows above 22, it seems to have moved to
~/.emacs.d/init.el
, ~ being the value of your environment variable HOME (see Control Panel → System → Advanced → Environment variables).
The file itself might not exist. In that case just create it.
You must create an emacs initialization file. One is not automatically created.
I had a similar issue and this answer tracks down what I did.
My issue was my ~/.emacs.el file was not loading. Strange because this has always worked for me.
This question/answer helped me but I had to put my init file in the %USERPROFILE%\AppData\Roaming\.emacs.d\init.el because this is apparently the default behavior on Windows.
To troubleshoot this, I ran the following in the emacs *scratch* buffer.
user-emacs-directory
"~/.emacs.d/"
When I saw user-emacs-directory was ~/.emacs.d, I simply moved my .emacs.el file to %USERPROFILE%\.emacs.d\init.el. But this still didn't work.
I continued with expand-file-name as shown below:
(expand-file-name user-emacs-directory)
"c:/Users/pats/AppData/Roaming/.emacs.d/"
Got to love how Windows works. (not) So I moved my emacs.el file to the %USERPROFILE%\AppData\Roaming\.emacs.d\init.el and this worked. The file was now being read. But I got other errors because my initialization file loaded other (personal emacs) files (in ~/myenv/emacs/*.el.
Warning (initialization): An error occurred while loading ‘c:/Users/pats/AppData/Roaming/.emacs.d/init.el’:
Hum... Seems like all my files ~/myenv/emacs/*.el would need to be moved in order for this to work but I didn't want to do that. Then I realized that because the HOME environment variable was not set, emacs was performing its default behavior.
SOLUTION
Once I set my windows HOME environment variable to %USERPROFILE% everything began to work like it has for the past 25 years. :-)
To set the HOME environment variable, I typed WindowsKey+"edit environment variables for your account" to open the Environment Variables dialog box, and entered HOME=%USERPROFILE%.
Now my emacs initialization file .emacs.el is is back to its rightful place $HOME/.emacs.el and not in %USERPROFILE%\AppData\Roaming\.emacs.d\init.el
To be fair, if Windows had just one place to put files for user installed packages the solution of making HOME=%USERPROFILE\AppData\Roaming might be acceptable, but because some applications use %USERPROFILE%, some use %USERPROFILE\AppData\Roaming and others use %USERPROFILE\AppData\Local it just makes it difficult to know where to find your configuration files.
I prefer having everything in my %USERPROFILE% or $HOME directory.
Another similar question was here:
Emacs init.el file doesn't load
As kanja answered, the path to this file is stored in the user-init-file variable (or if no init file exists, the variable contains the default value for where to create it).
So regardless of which of the possible init file names you are using, and which directory it is in, you should be able to visit your init file with:
M-: (find-file user-init-file) RET
Or display its full path in the echo area with:
M-: (expand-file-name user-init-file) RET
On Emacs 23 and Windows 7 it only works if you set:
HKCU\SOFTWARE\GNU\Emacs\HOME
After Emacs 27.1, emacs has started respecting the $XDG_CONFIG_HOME. The init file or the init directory can now be found in $XDG_CONFIG_HOME/emacs/init.el.
In Windows $XDG_CONFIG_HOME could translate to %LOCALAPPDATA%.
In any case you can use the following emacs variables to find out the location of the your initialization file by M-x eval-expression
user-init-file
or the emacs configuration directory
user-emacs-directory
I've found that Emacs 22 will occasionally open either "C:\Documents and Settings\username\Application Data\.emacs", or just "C:\Documents and Settings\username\.emacs" on my XP machine. I haven't found an explanation for why it occasionally changes it's mind.
~ will always point to whatever the current instance of emacs thinks is HOME, but kanja's tip (C-h v user-init-file) will always tell you what ~/.emacs actually maps to.
On Windows 8.1, if Emacs is started from Windows Explorer, a shortcut or from cmd console it uses C:\Users\<USER>\AppData\Roaming.emacs init file. When I start Emacs from PowerShell, Emacs looks for its init file in C:\Users\<USER> folder. The fix to this issue was to set the HOME user environment variable (Control Panel\System and Security\System->Advanced system settings->Advanced->Environment variables) to C:\Users\<USER>. After this change, no matter how I start Emacs, it uses the same init file (see the accepted answer of this question)
On Windows XP it's:
C:\Documents and Settings\yourusernamehere\Application Data\
There is a list of directories based on your Windows version and extra information:
http://www.gnu.org/software/emacs/manual/html_node/emacs/Windows-HOME.html
For WIndows7& Emacs26.3:
if HOME environment is set, then the .emacs file should be in that folder.
otherwise, it should be in c:\.
In both cases, if .emacs is not there, _emacs should be used.
This is because we cannot create .emacs file according to the windows file naming rules.(but we can download or copy it from somewhere else).

emacs not picking up my init.el file on windows

I have my emacs.d folder located at:
C:\Users\<loggedin_user>\AppData\Roaming\.emacs.d
In this folder, I have my init.el file but it is not being picked up by emacs.
Is there another step I am missing, do I need to set an environment variable or something?
When I enter C-x d ~/ RET I end up at
C:\Users\<loggedin_user>\AppData\Roaming\
If I move the init.el file there, it is still not picked up. I have a deliberate error in the file that is not causing emacs to crash when it is opened.
Most likely you have an old ~/.emacs file somewhere else which Emacs ends up using in preference to the other one.
You probably want to check the value of user-init-file which will tell you which file Emacs ended up using as "the ~/.emacs file".
I suggest you report this as a bug, requesting that when several files are found as possible init file, Emacs should not just pick the first and ignore the others but should at least emit a warning about the fact that it ignored the others.
This is tricky on Windows 10 but I solved since I was suffering from same issue.
I created an Environment Variable called HOME with the path C:/user/<username> in the box "User variables for " create a new one
Just open with double click any file that is by default opened with Emacs and it will take few seconds to load then take changed on the init.el
create an init.el with just one line of code like:set-background-color "honeydew"
to test this, first before doing something more complex.
Hope That It Helps!
On Windows, Emacs is started with some Properties defined, found when you right-click the executable on your windows system. There you can define the
execution-directory, e.g. "C:\Users\loggedin_user\" (in parantheses)
where emacs executes
and looks for the .xemacs (.emacs) directory, where it find its init.el. (I had to create an .emacs File in my Windows Home Directory, which is defined in the Windows HOME Environment)
And where you can define the startup instructions (like (setenv "HOME" "c:/Users/Username/") ) etc.
If you configure that, the next time, emacs starts from the directory, you defined, with the initialisation-file
Windows 10 and Emacs 27.1 could not find .emacs.d: one more possibility, in my case %HOME% was set like HOME=%HOMEDRIVE%%HOMEPATH%. This redirection seems not to work and emacs was using literally C:\Users\<loggedin_user>\%HOMEDRIVE%%HOMEPATH% for searching .emacs.d. I did not dare to edit %HOME% but created link:
C:\Users\username> cd %HOME%
You perhaps need to remove some files in C:\Users\<loggedin_user>\%HOMEDRIVE%%HOMEPATH% which emacs already created.
Create link:
C:\Users\<loggedin_user>\%HOMEDRIVE%%HOMEPATH%> mklink /d .emacs.d ..\.emacs.d

emacs on Windows: .emacs is no valid file name

I've found out where to put my .emacs file, but it seems it can't begin with a ".".
I tried naming it "emacs" or "_emacs", but how can I find out if it is used?
You can always create the file using Emacs itself: C-x C-f ~/.emacs. The ~ represents your home directory, which you can set as environment variable HOME.
Have a look at this page and this one for start up instructions.
If you are creating a file in Explorer, it won't allow you to use a .name (gives this error).
A simple work-around, if you have bash (cygwin, git-bash, or any other variant) installed is to use that to rename the file. It may also work in powershell or command prompt, I've not tested those.
Files can start with '.', this doesn't cause any trouble alone, but explorer won't let you name them with it.
Windows Explorer disallows the creation of filenames starting with a dot. A simple workaround with builtin Windows tools is to create the file with a dummy name (eg. _emacs), then use cmd.exe to rename it:
cd path/to/file
ren _emacs .emacs
Recent versions of windows (e.g. Windows 7) seem to allow creation of a .emacs file using windows explorer. When creating/renaming the file simply enter .emacs. instead of .emacs.
To test if the .emacs that you are editing is the .emacs that is being loaded, you could put the following elisp command in it:
(minibuffer-message "it worked")
Now exit and restart emacs, while watching the minibuffer at the bottom of the screen to see if it appears (it will only appear for 2 seconds).
Windows allows the creation and use of that type of file, but Windows Explorer does not allow a file to be named to that using Windows Explorer. Use another tool (like the command line, or emacs) to create the file with that name.

a question about clearcase: how to open a file checked out in emacs?

I have a question about clearcase. in linux, I open a terminal, and use "xclearcase" command to lunch file browser of clearcase. Then I check out a file and I want to open it in Emacs, I know I should cd to the folder contains the checked out file, but before I do this, the terminal still effected by the "xclearcase" command, how could I type some commands now?
When you launch xclearcase, do so by adding a & to the end of it. This will make the shell send it to the background so you can do more stuff in your shell. E.g.
xclearcase &
That will allow you to further interact with your shell while xclearcase is running.
Also, if you're working in the terminal, I would recommend getting comfortable with cleartool for basic operations. For example, to checkout and edit a file:
cleartool co src/path/to/file.c
emacs src/path/to/file.c
Then, to checkin the file:
cleartool ci src/path/to/file.c
As Nemo mentions in the comments, the vc-clearcase Emacs mode allows you to checkout a file right from an Emacs session (C-x v v).
It will handle hijacked file, asking whether to keep the changes in said hijacked file through the question "Claim lock retaining changes?"
It will ask for a comment
It allows for checkouting a directory
It handle file with a -nocheckout rule on their config spec

How to set emacs to open new files in current instance on Ubuntu/Mint?

I want to keep emacs open most of the time, and then whenever I open a text file, python file, etc (from nautilus/finder), I want it to open as a new buffer in my current emacs instance, rather than starting a new instance.
I tried following this guide:
I wasn't really sure about what to do with the file, but what I tried was copying it to /usr/bin/emacs_openfile, adding #!/bin/sh to the first line, and running chmod +x emacs_openfile
However, it doesn't work for me and just opens a new instance, even though I was able to associate text files with this program.
On a sidenote, I set emacs as the default editor using this.
You want emacs client.
Basically, set emacsclient as your default editor, and add (server-start) somewere in your emacs config.
There needs to be a running Emacs instance for emacsclient to work, but if it's a hassle it's possible to have a headless Emacs launched at login.
Did you start server in emacs? Make sure that you add (server-start) to your .emacs or do M-x server-start from an existing EMACS session.
Conceptually, it's really easy, just do emacsclient file-name on the command line or where you name the program.
Just for your information, If you are using GUI version on Mac, the dir os emacsclient is below:
/Applications/Emacs.app/Contents/MacOS/bin/emacsclient