Emacs: Search Text

Interactive Search

isearch-forward 【Ctrl+s】

Interactive search text in current buffer.

While in isearch prompt:

• Ctrl+s → Jump to next occurrence
• Ctrl+r → Jump to previous occurrence.
• Ctrl+g → Exit and place cursor at original position.
• Enter → Exit and place cursor at current position.

• Ctrl+y → paste to the prompt.

Smart Case Sensitivity

in isearch, if the search text:

• has uppercase letter, then it is Case-Sensitive.
• else, Case-Insensitive.

Toggle Case Sensitivity

Alt+x toggle-case-fold-search

• When enabled, it is smart case. (the default.)
• When disabled, it is Case-Sensitive.

Remember to toggle it back.

Smart Character Equivalence

emacs has many settings that control character equivalence for isearch, such as whitespace equivalence, unicode chars equivalence e.g. e é, 1 ①.

• Emacs Init: isearch Whitespace Regex

Search Word in Computer Language Source Code (Symbol with Boundary Check)

Search Current Symbol

isearch-forward-symbol-at-point 【Alt+s .】

• Search the symbol under cursor, with boundary check.
• Boundary check means, if current symbol is “xy”, it will not find “xy2”.
• Emacs: What is Syntax Word vs Symbol

Search Symbol

isearch-forward-symbol 【Alt+s _】

search for a symbol with boundary check.

Interactive Search Sequence of Words

isearch-forward-word 【Alt+s w】

like isearch, but space is considered equivalent to newline, hyphen, lowline, comma, or other punctuations.

If you have isearch config set to whitespace equivalence, then this command is not very useful.

• Emacs Init: isearch Whitespace Regex

Interactive Search by Regex Pattern

Ctrl+u Ctrl+s

(this calls isearch-forward in regex mode.)

• Emacs: Universal Argument (C-u prefix arg)
• Emacs: Regular Expression Syntax

Non-Interactive Search (No Smart Features)

these are useful if you want to search text verbatim, ignore all smart equivalence of chars.

Alt+x search-forward

search text after cursor position.

Alt+x re-search-forward

search text after cursor position, using Emacs: Regular Expression Syntax

Reference

• Search (GNU Emacs Manual)