Regular Expressions

Reference: www.regular-expressions.info, Online tool.

• cat|dog: Alternates, cat or dog.
• \/[^\/]+$ Everything after last / on line.
• ^.*svn ci -m Variable prefix ending in "svn ci -m ".
• ^[^{]+\{\{ Find first (not last) {{ on each line.
• "last_updated": ".+[^,]$ Find lines with "last_updated": " and not ending in a comma.
• Use curly braces to specify repetition. Examples: [A-Za-z0-9]{32} 32-character alphanumeric; [1-9][0-9]{2,4} Number from 100 to 99999.
• exchange_rate not followed by a ,: exchange_rate(?!,).
• ^((?!affectv).)*$: Match all lines without string affectv.
• <!--[^>]*--> HTML comments.

Special Characters

• . Matches any character.
• ( This marks the start of a region for tagging a match.
• ) This marks the end of a tagged region.
• \n Where n is 1 through 9 refers to the first through ninth tagged region when searching or replacing. Searching for (Wiki)\1 matches WikiWiki. If the search string was Fred([1-9])XXX and the replace string was * Sam\1YYY, when applied to Fred2XXX this would generate Sam2YYY.
• \0 When replacing, the whole matching text.
• \b This matches a word boundary.
• \c A backslash followed on of the following becomes a character class (both inside and outside sets []).
  • d Decimal digits.
  • D Any char except decimal digits.
  • s Whitespace (space, \t, \n, \r, \f and \v).
  • S Any char except whitespace.
  • w Alphanumeric & underscore.
  • W Any char except alphanumeric & underscore.
• \x This allows you to use a character x that would otherwise have a special meaning. For example, \[ would be interpreted as [ and not as the start of a character set. Use \\ for a literal backslash.
• [...] Matches one of the characters in the set. If the first character in the set is ^, it matches the characters NOT in the set. A shorthand S-E (start dash end) is used to specify a set of characters S up to E, inclusive. The special characters ] and - have no special meaning if they appear first in the set. - can also be last in the set. To include both, put ] first: []A-Z-]. Examples:
  • [a-z] Any lowercase alpha; [^]-] Any char except - and ]; [a-zA-Z] Any alpha.
  • ^ Matches the start of a line (unless used inside a set, see above).
  • $ Matches the end of a line.
  • * Matches 0 or more times. For example, Sa*m matches Sm, Sam, Saam, Saaam and so on.
  • + Matches 1 or more times. For example, Sa+m matches Sam, Saam, Saaam and so on.
  • ? Matches 0 or 1 time(s). For example, Joh?n matches John and Jon.