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Character
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Definition
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Example
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Most characters
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Characters other than . $ ^ { [ ( | ) * + ? \ match themselves. If you need to match these special characters - precede them by \
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abc matches abc
\? matches ?
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^
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The pattern has to appear at the beginning of a string.
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^cat matches any string that begins with cat
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$
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The pattern has to appear at the end of a string.
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cat$ matches any string that ends with cat
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.
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Matches any character.
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cat. matches catT and cat2 but not catty
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[]
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Bracket expression. Matches one of any characters enclosed.
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gr[ae]y matches gray or grey
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[^]
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Negates a bracket expression. Matches one of any characters EXCEPT those enclosed.
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1[^02] matches 13 but not 10 or 12
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[-]
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Range. Matches any characters within the range.
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[1-9] matches any single digit EXCEPT 0
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?
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Preceeding item must match one or zero times.
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colou?r matches color or colour but not
colouur
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+
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Preceeding item must match one or more times.
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be+ matches be or bee but not b
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*
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Preceeding item must match zero or more times.
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be* matches b or be or beeeeeeeeee
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()
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Parentheses. Creates a substring or item that metacharacters can be applied to
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a(bee)?t matches at or abeet but not abet
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{n}
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Bound. Specifies exact number of times for the preceeding item to match.
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[0-9]{3} matches any three digits
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{n,}
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Bound. Specifies minimum number of times for the preceeding item to match.
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[0-9]{3,} matches any three or more digits
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{n,m}
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Bound. Specifies minimum and maximum number of times for the preceeding item to
match.
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[0-9]{3,5} matches any three, four, or five digits
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Alternation. One of the alternatives has to match.
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July (first|1st|1) will match July 1st but not July
2
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\n
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The newline character. (ASCII 10)
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\n matches a newline
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\s
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A single whitespace character.
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a\sb matches a b but not ab
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\d
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A single digit character.
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a\db matches a2b but not acb
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