~ / search / magiclesson 5/7

Very magic \v, very nomagic \V

Write regexes without a forest of backslashes, or search text exactly as written.

?how it works

In a normal Vim pattern, . * [ ^ and $ are special, but groups and most repeats need a backslash: $ $ \| \+ \{3}. Start the pattern with \v (very magic) and they all work bare, much like a regex in JavaScript or Python: \v(get|set)_\w+, \v\d{4}. In :s, \1 \2 in the replacement put back what each group matched.

\V (Very nomagic) is the opposite: after it, everything is literal except a backslash. /\Vv1.2.* finds exactly "v1.2.*". Use it for text full of dots, stars or brackets.

A few characters still need escaping. In a / search the / ends the pattern, so write \/; in a ? search it's ? instead, which makes ? handy for paths and URLs. A literal backslash is always \\. In :s you can pick another delimiter: :s#/usr/bin#/opt/bin#.

Building a tricky pattern? Search, look at what lights up, then press / and <Up> to bring the last pattern back and refine it. <Up> only recalls older searches that start with what you've typed so far.

The rule of thumb: \v when you mean a regex, \V when you mean the text.

⌨keys

`\v`	pattern: very magic (( ) \| + ? { } work without backslashes)
`\V`	pattern: very nomagic (only \ and the delimiter are special)
`\d \w \s \x \a`	digit, word char, space/tab, hex digit, letter
`\u \l`	uppercase letter, lowercase letter
`\1`	:s replacement: the text the first group matched
`/<Up>`	recall an older search (that starts with what you typed)
`/<Down>`	recall a newer search

Nin neovim

Neovim (like Vim) can open the search history in a small window with q/, where you edit an old pattern with normal Vim keys and press <CR> to run it. That window isn't available in this editor; <Up> and <Down> in the prompt are.

3 drills

Swap parts with \v groups: Rewrite every line with one :%s command, using a very magic pattern with groups and \1 \2 in the replacement.
Alternatives with \v: Make the change on every line that needs it with one :%s, using | (or) in a very magic pattern.
Search literally with \V: The target text is full of characters that mean something in a pattern. Land on it with one search.

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