31 lines
803 B
Bash
Executable File
31 lines
803 B
Bash
Executable File
#!/bin/sh
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echo '
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Character classes
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. any character except newline
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\w \d \s word, digit, whitespace
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\W \D \S not word, digit, whitespace
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[abc] any of a, b, or c
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[^abc] not a, b, or c
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[a-g] character between a & g
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Anchors
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^abc$ start / end of the string
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\\b \\B word, not-word boundary
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Escaped characters
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\. \* \\ escaped special characters
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\\t \\n \\r tab, linefeed, carriage return
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\u00A9 unicode escaped ©
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Groups and Lookaround
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(abc) capture group
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\\1 backreference to group #1
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(?:abc) non-capturing group
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(?=abc) positive lookahead
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(?!abc) negative lookahead
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Quantifiers & Alternation
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a* a+ a? 0 or more, 1 or more, 0 or 1
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a{5} a{2,} exactly five, two or more
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a{1,3} between one & three
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a+? a{2,}? match as few as possible
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ab|cd match ab or cd
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'
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