- When you start emacs from a shell, emacs inherits shell’s environment variables. (true on Windows, Mac, Linux)
- On Windows, when you start emacs from GUI, emacs also inherit environment variables, from the Registry.
- On Mac OS X, when you start emacs from GUI, emacs does not inherit environment variables from your shell, but does inherit the system-wide environment variables from 〔~/.MacOSX/environment.plist〕.
- On Mac OS X, you can start GUI emacs from shell, like this:
nohup /Applications/Emacs.app/Contents/MacOS/Emacs &. This way, it’ll inherit shell’s environment variables.
I want to be able to press a button, and have the current file executed or compiled. The file may be a Perl, Python, PHP, Bash, script, or Java code.
There are several shells for Emacs, but none can match the versatility and integration with Emacs like Eshell. Eshell is a shell written entirely in Emacs-Lisp, and it replicates most of the features and commands from GNU CoreUtils and the Bourne-like shells. So by re-writing common commands like
lsandcpin Emacs-Lisp, Eshell will function identically on any environment Emacs itself runs on.Unfortunately, there is a problem: Eshell is woefully underdocumented — a rare sight in GNU Emacs — so I’ve compiled this guide to help people make full use of what Eshell has to offer.
most emacs major modes have “hooks” mechanism. It means, you can have emacs automatically run some code, whenever the mode is loaded.
Here’s a example:
(add-hook ‘org-mode-hook ‘soft-wrap-lines) ; make org-mode wrap long lines
(defun soft-wrap-lines ()
“Make lines wrap at window edge and on word boundary,
in current buffer.”
(interactive)
(setq truncate-lines nil)
(setq word-wrap t)
)
another example, adding some personal keys to a major mode.
(add-hook ‘org-mode-hook ‘xah-org-mode-keys)
(defun xah-org-mode-keys ()
“my keybindings for org-mode. For `org-mode-hook’.”
(local-set-key (kbd “<M-up>”) ‘org-metaup)
(local-set-key (kbd “<M-down>”) ‘org-metadown)
(local-set-key (kbd “<M-left>”) ‘org-metaleft)
(local-set-key (kbd “<M-right>”) ‘org-metaright)
)
typically, if a mode is named “xyz-mode”, its hook is usually named “xyz-mode-hook”. You can find out for sure by loading the mode first, then call “describe-variable” on the hook name. Or, call “describe-function” on “xyz-mode” and go to the code and do a “list-matching-lines” for the word “hook”.
to elisp, a hook is basically just a variable, pre-defined in a major mode. The value of this variable is a list of symbols (function names). When a major mode is loaded, emacs will run all the functions.
You can look at the value of a hook anytime by calling “describe-variable”.
now, whenever you want to remove some hooks, you can do this:
(remove-hook ‘org-mode-hook ‘soft-wrap-lines)
select the line, and call “eval-region”.
whenever you made changes to the hook, you usually need to reload the mode for it to be in effect. Fastest way is simply to re-open that file.
This page shows you how to use emacs keyboard macro feature, with several examples of real world use.
A better Dired mode
Just for fun :D
Emacs is a excellent tool for file management. For example, listing files, copy/delete files, rename files, moving files, creating/deleting directory. Once you become familiar with it, you almost never go back to shell or the OS desktop for these tasks.
This page is a short, practical, tutorial of Emacs Lisp the language.
