Hello, I'm new and not very good at regular expressions, does anyone know how to do the following -

I need to replace any occurence of an "_" with "\_" as long as the preceding character is not already a "\".

Any ideas?

Thanks,
Sapan

(?<!\\)_

will find occurrences of _ that are not preceded by \.  Replace those with \_.

Thanks!  :-)

Uhm hang on, do you know how I would format that in vi?

Thanks,
Sapan

Personally, no.  But it looks as though this might help.

   http://sitescooper.org/tao_regexps.html

Roger