Regular Expressions/Shell Regular Expressions
The Unix shell recognises a limited form of regular expressions used with filename substitution:
|?||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.|
|*||An asterisk specifies zero or more characters to match.|
Some operators behave differently in the shell: The asterisk and hook operators do not not need to follow a previous character in the shell and they exhibit non traditional regular expression behaviour.
Unsupported Constructs: Within the shell, a compliment box is formed using the pling symbol. The shell does not support the use of a careted box for character list exclusion. In the shell, a caret symbol within a box will simply be treated as one of the characters within the character list for matching.
Use in Tools
Tools and languages that utilize this regular expression syntax include:
- Bourne compatible shells