Emacs: List/Delete Matching Lines

Alt+x list-matching-lines 【Alt+s o】 (alias of occur)

List all lines in the current file that matches a Regex text pattern.

Alt+x copy-matching-lines

Copy lines that matches a regex pattern.

Alt+x count-matches

Count matching lines. (alias of how-many)

Alt+x kill-matching-lines

Copy and delete matching lines

Alt+x delete-matching-lines

Delete lines that match a Regex. Works on text selection or starts at the line your cursor is on. (alias of flush-lines)

Alt+x delete-non-matching-lines

(alias of keep-lines)

Alt+x delete-duplicate-lines

Delete duplicated lines in text selection.

Clicking the line jumps to the match location.

Escape Regex Chars

All these commands use Emacs: Regular Expression to search. So, if you simply want to search plain words or phrases, and if your phrase contains any special regex characters, you need to escape them.

Here's common regex special characters that need backslash before to be considered literal:

. + * \ ? [ ]

Letter Case Sensitivity

• Emacs: Regular Expression Case Sensitivity

List Lines in ALL Buffers

Alt+x multi-occur if you want to list lines in ALL buffers.