,
ex(1), or
vi(1)The following table contains examples of basic regular expressions. A dot (.) represents the space character.
| Use this expression | If you want to match |
|---|---|
| ^$ | An empty line |
| ..* | One or more spaces |
| [^][-] | Any character except [, ], or - |
| [A-Z] or [[:upper:]] | Any uppercase letter |
| [1-9][0-9]\{2\}-[0-9]\{4\} | A local telephone number in the United States or Canada |
| [A-Z]\{3,} | Three or more uppercase letters |
| \(and.*\)\{2,3\} | Two or three occurrences of the word and, possibly separated by spaces |
| s/\([^.][^.]*\).\([^.][^.]*\)/\2 \1 | Swap two words in ed(1),
ex(1), or
vi(1) |
| [_A-z][_A-z0-9]* | A valid C-language variable name |