aez-notes

Emacs
Emacs Lisp
Spacemacs
Miscellaneous

Emacs

Keyboard macros

Start recording with C-x (.
Stop recording with C-x ).
Execute the recording with C-x e.

If you want to save a macro for later use, you can get a emacs-lisp definition of it with insert-kbd-macro.

Jargon

There is a glossary in the manuals, the nodes are Emacs > Glossary. The regex search entered with s is very useful here.

The daemon and the client

To start an Emacs daemon run emacs --daemon. To open a new frame run emacsclient -c, or to open a specific file emacsclient -c <path/to/file>.

Documentation

Running the info function will load the manuals. Although, C-h i brings you there much quicker. To start with you are in vim keybindings so can move around with hjkl, but apart from that you'll want to jump to emacs keybindings so you can use dubnpmlrsf[]<SPC> for greater flexibility navigation.

Info navigation

n next node
p previous node
[ and ] are for up and down levels of nodes
b to go to the start of a node
SPC to go to the end o a node
l last node before this one
s search with a regex
f find a node linked from here
m is a menu of linked nodes
u up a level of nodes
d go to the root node

Documentation on debugging

In the Emacs Lisp Intro there is a section, Debugging, which walks through the use of the built-in debugging facilities.

Emacs Lisp

See my Emacs Lisp notes.

Spacemacs

Configuration

My configuration for spacemacs is available as an org-mode file here. I have also written a small quick start guide for spacemacs as part of the ESS introductions project.

Startup

To put your own image on the splash screen you need to modify dotspacemacs/init, specifically you need to set the variable dotspacemacs-startup=banner to be a string of the full path to the desired PNG. A sensible place to put the image is ~/.emacs.d/core/banners/img. You can reduce the size of PNG to get a better fit with the following command.

convert -resize 50% foo.png bar.png

Here is the image I (previously) used. Now I use banner 100.

Welcome to
███████╗███╗   ███╗ █████╗  ██████╗███████╗
██╔════╝████╗ ████║██╔══██╗██╔════╝██╔════╝
█████╗  ██╔████╔██║███████║██║     ███████╗
██╔══╝  ██║╚██╔╝██║██╔══██║██║     ╚════██║
███████╗██║ ╚═╝ ██║██║  ██║╚██████╗███████║
╚══════╝╚═╝     ╚═╝╚═╝  ╚═╝ ╚═════╝╚══════╝

Default colour schemes

The hexcodes for the default colour schemes used by Spacemacs can be found in spacemacs/core/libs/spacemacs-theme/spacemacs-common.el

Miscellaneous

Completion with company producing unacceptable lag

Try adjusting company-idle-delay and company-minimum-prefix-length to prevent the backend being queried too often.

Change Logs

Emacs has built-in support for change logs which should be saved to a file called ChangeLog. From within the file you are editing, use C-x 4 a to open a new window with the change log file with the name, date and filename (and potentially function name) added.

Dired

DIRED CHEAT SHEET

Task	Command
Rename a file	`R`
Copy file	`C`
Make directory	`+`
Mark	`m`
Unmark	`u`
Flag for deletion	`d`
Execute deletions	`x`
Move up a directory	`^` or `-`

Moving multiple files

Suppose you want to move some of the files from directory X to directory Y.

Go to X in dired,
Mark the files you want to copy with m,
Copy them with C (yes that is a capital 'c'),
Select Y from the pop-up menu.

Searching for things with Dired

The following advice from the emacs manual may be useful if you are trying to locate some files.

To search for files with names matching a wildcard pattern use M-x find-name-dired. It reads arguments DIRECTORY and PATTERN, and chooses all the files in DIRECTORY or its subdirectories whose individual names match PATTERN.

There is also the grep command for searching within files and the find command for searching based on the filename.

Buffer menu

Ibuffer

Use ibuffer or SPC o f b to summon the Ibuffer menu.

The buffer menu is a built-in mode which provides features like Dired, but for working on buffers. By clicking on the column labels you can sort the buffers in helpful ways, you can use d to mark buffers for deletion and execute such instructions with x. Similarly files can be marked for saving with s and unmarked with u.

The s command opens a menu for sorting.

Buffer menu

Use list-buffers or C-x C-b to summon the buffer menu.

The buffer name and the visited file are clearly labelled, the letters CRM stand for current, read-only and modified.

Elfeed

RSS reader for emacs. To start the elfeed application use SPC a f. Mnemonic: [a]pplication [f]eed. Set up a list of feeds by setting the elfeed-feeds variable.

Shortcuts

Keys	Description
`SPC a f`	Enter elfeed
`r`	Mark as read
`u`	Mark as unread
`g r`	Refresh feed
`s`	Search feed
`+`	Add a tag

Configuration

You can put the configuration of elfeed in a seperate file and then load it from your init. In Spacemacs, this means adding the following to your dotspacemacs/user-config:

(load-file "<path/to/config.el>")

where the configuration file sets the elfeed-feeds quantity to be a list of URLs. NOTE! If you want to add tag specific faces for the entries, you need to include (require 'elfeed-search) at the top of the configuration file.

Automatic tagging of entries

The elfeed-new-entry-hook provides a way to automatically tag new entries, for example, by checking if the title and content contain particular words. The following snippet is taken from the author's blog demonstrating how to do this.

(defun score-elfeed-entry (entry)
  (let ((title (elfeed-entry-title entry))
        (content (elfeed-deref (elfeed-entry-content entry)))
        (score 0))
    (loop for (pattern n) in '(("alloy" 1)
                               ("machine learning\\|neural" 1)
                               ("database" 1)
                               ("reproducible" 1)
                               ("carbon dioxide\\|CO2" 1)
                               ("oxygen evolution\\|OER\\|electrolysis" 1)
                               ("perovskite\\|polymorph\\|epitax" 1)
                               ("kitchin" 2))
          if (string-match pattern title)
          do (incf score n)
          if (string-match pattern content)
          do (incf score n))
    (message "%s - %s" title score)

    (cond
     ((= score 1)
      (elfeed-tag entry 'relevant))
     ((> score 1)
      (elfeed-tag entry 'important)))
    entry))

(add-hook 'elfeed-new-entry-hook 'score-elfeed-entry)

Magit

I have some notes on git, but this section is about the emacs package magit which is like a git client. To get to the magit status buffer use SPC g s.

Keys	Command	Description
`SPC g s`	`magit-status`	Open the status buffer
`F p`	`magit-pull-from-pushremote`	Pull commits from remote
`s` and `u`		Stage and unstage files
`c c`		Create commit
`, k`		Kill (cancel) a commit
`C-c C-c`		Confirm commit
`p p`		Push commits to remote
`l l`		Show commits graphically
`b b`		Checkout a branch

The following definition tells magit to open the status buffer in a full frame.

(setq magit-display-buffer-function #'magit-display-buffer-fullframe-status-v1)

Spell checking

Configuration

Add spell-checking to the layers list. By default it will look for aspell on the path (which is the GNU replacement for ispell.) The program that will be used is described by ispell-program-name. The dictionary that will be used is defined by ispell-dictionary. I have the following settings for spell checking

(spell-checking :variables
                spell-checking-enable-by-default nil
                enable-flyspell-auto-completion t)

Usage

I need to explicitly use SPC t S to toggle on spell checking. To spell check the buffer I use SPC S b. Leaving the point over a misspelled word will bring up a list of potential corrections.

To add a new word to a private dictionary use M-$ to bring up the list of potential solutions and then press [i]nsert to add the word to a private dictionary.

Spray

Speed reader for emacs. Enable this by adding speed-reading to your configuration.

Keys	Description
`SPC a R`	Start spray
`SPC`	Pause
`f`	faster
`s`	slower
`h`	back (vim left)
`l`	forward (vim right)
`q`	quit

Yasnippet

There is a single snippet per file, there is a convenience function for creating new snippets: yas-new-snippet. The name is a human readable description and the key is the keyword you'll use to invoke the snippet. When writing a snippet, tab-stop fields (e.g., $1, $2, etcetera,) are used to specify additional data.

For spacemacs, the snippets are saved in /home/aez/.emacs.d/private/snippets/<major-mode>. Finally, use yas-reload-all to reload all of the snippets in that directory. Finally, to invoke the snippet there is functionality provided by helm with the spacemacs/helm-yas which is bound to SPC i s which will bring up a search option.

Word count

To count the words in a selected region use M =

Multiple cursors

Use the g r functions to set up some cursors then use the SPC s e to enter the editing mode for them. This seems to have been a source of confusion for many users….

aez-notes

Table of Contents

Emacs

Keyboard macros

Jargon

The daemon and the client

Documentation

Info navigation

Documentation on debugging

Emacs Lisp

Spacemacs

Configuration

Startup

Default colour schemes

Miscellaneous

Completion with company producing unacceptable lag

Change Logs

Dired

Moving multiple files

Searching for things with Dired

Buffer menu

Ibuffer

Buffer menu

Elfeed

Shortcuts

Configuration

Automatic tagging of entries

Magit

Spell checking

Configuration

Usage

Spray

Yasnippet

Word count

Multiple cursors