|}

Represents zero or more occurrences of regular expression directly preceeding the asterisk (<code>*</code>). By itself, it does not match anything - it is NOT a wildcard. It is used in conjunction with literal matches, a period or other special characters. Some examples of asterisk in regular expressions:

|}

Enclose a character class or group, similar to the shell. Any single character within the brackets will be matched. Hyphen can be used for defining a range of characters. Most special characters lose their special meaning. The caret sign at the beginning of the list means exclusion (<code>[^a]</code> means ''do not match a''). Some examples of square brackets in regular expressions are:

|}

Matches strings at the end of the line, (anchoring matches to the end of the line). Examples of dollar in regular expressions are:

|}

Parentheses can be used to create bracketed regular expressions. The parentheses group the regular expression inside. The parentheses are not matched, only what is inside. Grouping offers alteration/choice represented by the pipe (|). When a grouped expression is followed by a quantifier such as the asterisk, the quantifier applies to the entire group Examples of grouping with and without alteration are:

<blockquote><code>grep</code> requires the <code>-E</code> option to enable grouping

</blockquote>

= Search and Replace in vi =