You can use meta-characters in the 'Search For' field:

. any character except newline + one or more times
* zero or more times ? zero or one time
{n} match exact n times {n,m} at least n, at most m times
| pipe: a|b matches a or b - hyphen, match a range of chars
^ beginning of a line $ end of a line
[...] one of the char's of a set [^...] negated character set
\b word boundary \B word non boundary
\d numeral [0-9] \D non numeral [^0-9]
\s single white space \S single non white space
\w [A-Za-z0-9_] \W [^A-Za-z0-9_]
(...) grouping are stored as $1..$9 \. escape a meta char

The 'Replace with' field can use $1..$9 as a backreference to parentheses of 'Search for' field.


Example:

Search for /abc|def/ will match the word 'abc' or the word 'def'
Search for /bwiki/b will match the word 'wiki' but not the word 'jspwiki'.
Search for ^[IVXMDCL]+\. will match any combination of roman numeral char's followed by a period
Search for /(-?\d+)(\d{3})/ and replace with $1,$2 to insert commas in large integers.

This is the EditFindAndReplaceHelp page.

More info on regular expressions, JavaRegularExpressions, and the RegExp Sandbox