I am wondering what are the special characters in the replacement ( second string) string in when I use grep in TextWrangleor Perl or other such substitutions.
Example:
perl -0777pe 's/\r\n/\n/g'
Other than the \ in the second string ( the \n part , what are special characters. What must I escape besides \ ???
Robert
any regexp special character that you want to use literally must be escaped. E.g. if you want to search for a literl period you need to use \. (because a period is a regexp wildcard) and if you want to use a literal bracket '[' you have to use \[ (because brackets are regexp character range specifiers). In your particular case it doesn't look like anything else needs to be escaped.
if you're learning regexp, look through this tutorial. More than you'll ever want to know...
TextWrangler -> Help -> TextWrangler Help -> Grep -> Searching with Grep, then scroll down to "Writing Replacement Patterns"
Perl regular expressions replacement fields accept variable names
s/old/${new}/
Can substitute patterns found in the search side
s/ab(.*)yz/pq${1}rs/
There is most likely a world of stuff you can do with Perl, but those are the ones I tend to use mostly. You might find this useful <http://docstore.mik.ua/orelly/perl3/lperl/ch09_06.htm> as well as other Google searchs for "Perl Substitutions"
replacement string in grep
