How do I run a search and replace only within a visually selected region?

Explanation

When you make a visual selection and then type :, Vim automatically inserts '<,'> as the range — the marks for the start and end of the last visual selection. Any substitute command you run with this range will affect only the selected lines.

How it works

• '< — the mark for the first line of the last visual selection
• '> — the mark for the last line of the last visual selection
• :'<,'>s/old/new/g runs the substitution only within those lines
• After leaving Visual mode, '< and '> persist — you can re-use them without reselecting
• Add the c flag (:'<,'>s/old/new/gc) to confirm each replacement interactively

Note: The range is line-based — even a character-wise visual selection uses the start and end lines, not the exact characters. For exact column-range substitution, use \%V (see tip below).

Example

You have a config file and want to change true to false only in the [production] section. Select those lines with V + motion, then:

:'<,'>s/true/false/g

Lines outside the selection are untouched.

Tips

• Use \%V in your pattern to constrain to the exact visual selection (character-wise): :'<,'>s/\%Vold/new/g
• The marks '< and '> can be jumped to directly: '< moves to the first line, `< moves to the exact character
• Combine with :g for more power: :'<,'>g/TODO/d deletes all TODO lines within the selection
• After a visual substitute, press gv to reselect the original region for further operations