What's the use of emacs -batch - emacs

I'm trying to understand the difference between this two lines of code:
emacs --batch -l package.el
emacs -l package.el
Thanks a lot. Why -batch is needed here?

The -batch command line option stops Emacs from opening an editor window. This allows you to write scripts in Emacs Lisp, scripts that you otherwise would have used Ruby, Perl, or Python for.
Just out of the hat, an example that use the -batch option is e2ansi, a package that allows the more and less command to render a file with colors using ANSI sequences, based on the syntax highlighting Emacs performs. Clearly, this would not have worked if Emacs would have opened up a window when started.

Related

Run emacs command in terminal

I'm using Emacs Muse for work reasons and I don't really enjoy editing my .muse files in emacs.
I haven't found alternatives to publishing .muse files in another editor.
Is it possible to run Emacs commands from outside Emacs almost as if using it as a sort of interpreter?
I want to be able to go to the terminal and run something like:
> emacs -ne file_with_command file_to_publish.muse
The command in question is M-x muse-project-publish-this-file
edit: In Emacs, this command also has inputs that it prompts me to give one at a time. It's the style of publishing (html in my case) and the directory where the publication will go to.
muse-project-publish-this-file is not design to use in batch mode.Use muse-publish-file instead.
First,
git clone https://github.com/jwiegley/muse /path/to/muse
Then create script.el with content
(add-to-list 'load-path "/path/to/muse/lisp")
(require 'muse-publish)
(muse-publish-file "file_to_publish.muse" (muse-define-style "newstyle" nil) "/path/to/publish/directory")
notice is /muse/lisp not muse.
Last, emacs --batch -l script.el

Emacs shell behavior

I am using cygwin on windows 7. I have a question regarding the Emacs shell.
Whenever I use the shell inside of the Emacs(M-x shell)
It echo pwd directory after prints out the result.
I found it very annoying since it distracts me.
e.g.
$ ls
workspace
^[]0;~/cs61bl^G
myname#pc ~/cs61bl
Is there any way to remove these lines?
^[]0;~/cs61bl^G
myname#pc ~/cs61bl
When using Emacs, try using the eshell: M-x eshell. The eshell does not suffer from this problem.
You might be looking for "shell-dirtrack-mode". You can either do an M-x shell-dirtrack-toggle or (shell-dirtrack-mode 1) in your init file. Recent emacs versions seem to disable it by default.
There is this file http://www.emacswiki.org/emacs/setup-cygwin.el that simplifies setup of various packages in Emacs (including shell) to use cygwin. Also try not to use ANSI sequences in your PS1 prompt because Emacs shell mode wouldn't interpret them, something like
export PS1="\h \W\$ "
should do.

Changing the initialization location of Emacs

I used to take the Programming languages course on Coursera and for the sake of the course i installed SML-Mode.
Now, I'd want to set up a Clojure environment in Emacs but instead of initializing Emacs from ~/.emacs.d, it initializes from the Users/karthik/Documents/sml-mode/sml-mode-startup
I deleted the sml-mode folder and on Emacs startup it shows me a warning about the files not being present. How I do point Emacs to load Emacs Live from the home folder.
I'm an Emacs newbie.
One easy way to do it, is
save you closure settings in /some/dir/my-closure-settings.el and call emacs as the following (to learn about -q -l , try emacs --help )
$ emacs -q -l /some/dir/my-closure-settings.el
or even placing an alias in bashrc,
$ alias closure-emacs='emacs -q -l /some/dir/my-closure-settings.el'
$ closure-emacs # will start emacs with your closure settings.
As you progress in learning some elisp, you will want to do it in one folder.
Assuming you installed Emacs yourself, and this SML-mode was an independent package, then I would speculated that it may have modified your site-start.el.
See if running emacs --no-site-file makes a difference.
If that's the issue, you can visit the file with:
M-: (find-library site-run-file) RET
You might also check:
C-hv user-emacs-directory RET
when running emacs in various ways:
emacs
emacs --no-site-file
emacs -q
emacs -Q
Unless it's a custom binary, at some point it should tell you "~/.emacs.d/"
Installing SML-mode does not change the place of the main initialization file, which is one of ~/.emacs or ~/.emacs.d/init.el. So look at those files (which ever of the two is present), and if none is present, then just create it and add what you need in it.
BTW, it looks like you're using an old sml-mode package (the newer one doesn't have an sml-mode-startup.el file). So please try and make sure the documentation that pointed you to that mode is updated: nowaday sml-mode should be installed from GNU ELPA, i.e. via M-x package-list or M-x package-install.

How to navigate perl code with cscope in emacs?

I have been a VIM user for 4 years, but have been trying to learn emacs. My project is fully written in perl and I am trying to get the cscope working in emacs for perl.
I don't have any problem navigating perl from VIM.“cs add cscope.out” from vim command mode does the job for me. In emacs though, with the same cscope database (which has both C++ and perl symbols) emacs perfectly recognizes my C symbols (M-x M-x cscope-find-global-definition). But for perl symbols, I am getting the below error .
Error:
Finding global definition: somePerlFunction Search complete.
Search time = 0.92 seconds.
No matches were found.
Does emacs supports perl code navigation? If not, isn't it a major drawback? Can someone please help?
Yes, Emacs supports cscope, there are several options:
http://www.emacswiki.org/emacs/CScopeAndEmacs
I've just tested xcscope.el on GNU Emacs 24 and it seems to be working fine.
If you already have a cscope database, I suggest you run cscope from the command line, using the -d flag:
cscope -d
Use the 'Find this global definition' option to search for your symbol, if you don't get any results then the issue is with cscope, not Emacs. If you do find results, please provide more detail, e.g. which method of integrating cscope with Emacs you are using, which version of Emacs, and provide sample perl code which can be used to reproduce the problem.
You may also want to investigate cedet:
http://cedet.sourceforge.net/

.emacs Edit to Always Start Emacs in Terminal Mode?

I use emacs as my editor-of-choice, and since I'm doing a lot of work in a terminal I always run emacs as
emacs -nw
so that it runs in the terminal instead of in a window.
I'd like to just run emacs and have it know that it should run in a terminal. My question is - how do I edit my .emacs file so that this is the default behavior?
You can't do this in the .emacs file. By the time that file is being parsed, the "chosen" emacs binary is already running.
You can install the emacs-nox package as one commenter suggests, or create an alias in your shell so that "emacs" is always treated as "emacs -nw".
Randy
I'm using a bash alias instead of .emacs to do that.
Add this line to your ~/.bashrc.
alias emacs='emacs -nw'
There is any easy way to solve the problem in general that has nothing to do with emacs at all and will work for any program that can choose between running in the console vs X:
unset DISPLAY
Of course you may not want to put that in your configuration file to be applied globally to all your shell sessions, so if you want it to apply to only emacs, then either call it from the command line like this:
DISPLAY= emacs
note the space!!! if you leave the space out it means you're setting the DISPLAY to emacs instead of setting DISPLAY to nothing... this command is a shorthand for:
DISPLAY=; emacs
So either use the above from the command line(s) or put that in a wrapper script that would look something like this:
#!/bin/bash
unset DISPLAY
exec emacs
I recommend the exec there because it will replace your wrapper script with emacs; to see the difference between the two you can run:
pstree -p
When I was first setting up a "emacs -nw" alias for emacs in windows I got stuck in a situation where I thought tototoshi's explanation hadn't worked. Yet all that was required was a restart of my terminal. Therefore, i think its worth mentioning that in windows (at least) if you are using emacs within the git bash terminal to create the .bashrc file and add "alias emacs='emacs -nw" to it (as tototoshi mentions) you have to close and reopen your terminal for it to work.