Useful Emacs Commands

This page serves as on-line documentation for some Emacs commands that I always have a hard time remembering. It evolved from “notes to myself” posts on my blog Irreal.

Commands for Matching Lines


COMMAND	ALIAS	ACTION
keep-lines	delete-non-matching-lines	Delete lines not matching regexp
flush-lines	delete-matching-lines	Delete lines matching regexp
how-many	count-matches	Count lines matching regexp
occur	list-matching-lines	Show lines matching regexp in another buffer
highlight-lines-matching-regexp	hi-lock-line-face-buffer	Highlight lines matching regexp
multi-occur		Occur on multiple buffers
multi-occur-in-matching-buffers		Occur on buffers chosen by regexp

Deleting Lines and Parts of Lines


KEY SEQUENCE	ACTION
【`Ctrl`+`0` `Ctrl`+`k`】	Delete from point to beginning of line
【`Shift`+`Ctrl`+`Backspace`】	Delete entire line the point is on

Miscellaneous Text Commands


KEY SEQUENCE	COMMAND	ACTION
【Meta+o Meta+s】	center-line	Center line (n lines with prefix n)
【`Ctrl`+`Meta`+`w`】	append-next-kill	Append next kill
none	linum-mode	Turn on line numbers in left fringe

Register Commands

Specify a prefix on copy/move commands to delete the original.


KEY SEQUENCE	FUNCTION
【Ctrl+x r Space ρ】	Copy position to register ρ
【Ctrl+x r j ρ】	Jump to the position in register ρ
【Ctrl+x r s ρ】	Copy/Move region to register ρ
【Ctrl+x r i ρ】	Insert object in register ρ at point
【Ctrl+x r r ρ】	Copy/Move rectangle to register ρ
【Ctrl+x r w ρ】	Copy current frame configuration to register ρ
【Ctrl+x r f ρ】	Copy all frame configurations to register ρ
【Ctrl+u N Ctrl+x r n ρ】	Insert N into register ρ
【Ctrl+u I Ctrl+x r + ρ】	Increment register ρ by I

Using `set-mark-command` to Remember Locations


KEY SEQUENCE	ACTION
【`Ctrl`+`Space` `Ctrl`+`Space`】	Push current position onto mark ring
【`Ctrl`+`u` `Ctrl`+`Space`】	Return to previous position in the same buffer
【`Ctrl`+`x` `Ctrl`+`Space`】	Return to previous position, which may or may not be in the same buffer

Useful Help Commands


Command	Action
【`e`】	View `Messages` buffer
【`F`】 CMD	View Info node documenting CMD
【`r`】	View Emacs Manual

Also: elisp-index-search and emacs-index-search

Emacs Syntax Table

These aren't really commands but I always have a hard time finding this table in the built-in documentation so I'm listing it here.


SYNTAX CLASS	CHARACTER DESIGNATION
Whitespace Character	`-` (hyphen) or ␠
Word Constituent	`w`
Symbol Constituent	`_` (underscore)
Punctuation Character	`.`
Open Parenthesis	`(`
Close Parenthesis	`)`
String Quote	`"`
Escape-Syntax Character	`\`
Character Quote	`/`
Paired Delimeter (TeX $)	`$`
Expression Prefix	`'`
Comment Starter	`<`
Comment Ender	`>`
Inherit Standard Syntax	`@`
Generic Comment Delimiter	`!`
Generic String Delimiter	`\|`