RegExp cheat-sheet

RegExp

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RegExp cheat-sheet
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^         beginning of line
$         end of line

.         any character

*         zero or more
?         zero or one
+         one or more
{n}       n times
{n,}      n or more times
{n,m}     n or no more than m times

[all_of_above]?     consuming as little input as possible
[all_of_above]+     no input is returned for backtracking - all consumed

\x        where x = [1,9] matches the same input as subexpression x
    eg.:
        ^(a*).*\1$      
                    matches             aaabbaaa
                    does not match      aabbaaa

|         or, eg.: a(b|c)

[abc]     only the characters a,b and c
[a-d]     the characters from a to d
[^a-e]    all characters but the ones from a to e


sequence  equals

\d        [[:digit:]]
\l        [[:lower:]]
\s        [[:space:]]
\u        [[:upper:]]
\w        [[:word:]]
\h        Horizontal whitespace
\v        Vertical whitespace
\D        [^[:digit:]]
\L        [^[:lower:]]
\S        [^[:space:]]
\U        [^[:upper:]]
\W        [^[:word:]]
\H        Not Horizontal whitespace
\V        Not Vertical whitespace