Regular Expressions/Shell Regular Expressions

The Unix shell recognises a glob syntax for use with filename substitution. With the extglob extension of ksh and bash, it is equivalent to a basic form of regular expression in expressiveness. + Operators Operator Effect? The hook operator specifies any single character.[ ] boxes enable a single character to be matched against a character lists or character range.[! ] A compliment box enables a single character not within in a character list or character range to be matched. A non-standard equivalent, supported by GNU bash, is the caret syntax [^ ].*An asterisk specifies zero or more characters to match.?(pattern-list) Matches zero or one occurrence of the given patterns. extglob extension.*(pattern-list) Matches zero or more occurrences of the given patterns. extglob extension. +(pattern-list) Matches one or more occurrences of the given patterns. extglob extension.@(pattern-list) Matches exactly one of the given patterns. extglob extension.!(pattern-list) Matches anything except one of the given patterns. extglob extension. Differences from common regular expressions are: The asterisk and hook operators mean different things. The compliment bow is formed using the exclamation mark (!) in the POSIX standard, not a caret (^). Some shells, such as GNU bash, allow the caret to be used as an extension. The extglob extensions are not standard. They are only available in Korn shell (enabled by default) and GNU bash (enabled via shopt -s extglob). Use in Tools Tools and languages that utilize this regular expression syntax include: For the general glob syntax, all POSIX "bourne-compatible" shells. For the extglob part, Korn shell and bash. Links Bash Pattern Matching at gnu.org Guide_to_Unix/Explanations/Quoting_and_Filename_Expansion#Filename_expansion