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Is it possible to search a string that is a regex, without escaping all the fancy characters?

For example, I want to find this string in my source file: ^[\d\| *]$, without escaping \, $, etc.

I would like to just copy and paste the regex and get the result.

ib.
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Luc M
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  • "I would want to copy/paste the regex and get the result" -- What does that mean? Why are you so opposed to escaping special characters? – Tim Pote Jun 19 '12 at 02:10
  • @TimPote I would like to copy a regex from a source file and search for these characters. I would to type `:/` and paste the regex copied. – Luc M Jun 19 '12 at 02:13
  • @TimPote I'm not opposed to escape special characters. The example given is very simple. It's painfull when you have a complex regex and have to escape special characters. You never know if you did an error or the regex that you're looking for is not in the file. – Luc M Jun 19 '12 at 02:21
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    Yeah I figured out why you didn't want to escape those characters when I figured out what you meant by "copy/paste the regex". Have you looked at vim's `very nomagic` (`\V`) option? That should bring you a lot closer to a solution, although it won't fix having to escape backslashes. – Tim Pote Jun 19 '12 at 02:24
  • I found this question interesting and had a go. I found the \V option. But then it seems `|` is still magic in some way at least. Searching with `/\V^[\d\| *]$` put the search cursor on the space. – azhrei Jun 19 '12 at 02:27
  • @azhrei It's not the `|` that's magic, it's the `\|`. That's why I said it won't fix the backslash issue. [This answer](http://stackoverflow.com/a/1550930/836738) has an interesting solution for that, but it seems unduly complicated... – Tim Pote Jun 19 '12 at 02:29

4 Answers4

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What you want is a grep that searches for matching strings, rather than attempting to match a regular expression. With GNU grep, you can invoke the command with the -F or --fixed-strings flags, or just invoke the command as fgrep instead. The following are all equivalent:

grep -F '^[\d\| *]$'
grep --fixed-strings '^[\d\| *]$'
fgrep '^[\d\| *]$'

Fixed-string searches are exactly what you need when you want to match code that represents a regular expression, or when you want a faster grep that doesn't need the advanced matching capability of a regular expression engine.

Todd A. Jacobs
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There is an easy way to avoid special treatment of the characters in Vim regular expressions. The \V specifier allows to switch interpretation of the rest of the pattern to the “very nomagic” mode, which means that every character but the backslash is understood literally.

Therefore, one can set the last search register accordingly:

:let @/ = '\V' . escape('^[\d\| *]$', '\')

and use n and N for searching immediately.

ib.
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2

You can use the command line tool fgrep (“fast grep”),

ib.
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kev
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1

Supposing you have yanked the regexp to search for to the default register (@"), you can do this:

/\V<C-R><C-R>=escape(@", '/\')<CR><CR>

The \V starts a "very nomagic" search, where only atoms starting with a backslash have special, non-literal meaning. The escape() renders all those contained backslashes ineffective (and escapes / which would otherwise end the search pattern), so that this is a purely literal search. The text is inserted via Ctrl+R= into the search command line.

Ingo Karkat
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  • The suggested command does not work correctly for all cases. When the text to search contains backslashes, they are not escaped and, thus, could have a non-literal meaning. Try using the command when the default register contains `\d`. It will look for decimal digits, not for backslash followed by the letter 'd', as it is supposed to. – ib. Jun 19 '12 at 11:24
  • @ib: Doh, you're right. The backslash was omitted in the command. I've edited my answer. – Ingo Karkat Jun 19 '12 at 14:12