Special characters: [ ] ( ) { } - + * . ^ $ ? | \
Pattern-Matching Operators:
Regular expressions:
s⁄⁄⁄ modifiers:
⁄i Ignore alphabetic case (when matching).
⁄m Let ^ and $ match next to embedded \n. ^ for beginning, and $ for the end of the line. . matches everything except newline.
⁄s Let . match newline and ignore deprecated $*.
⁄x Ignore (most) whitespace and permit comments in pattern.
⁄o Compile pattern once only.
⁄g Replace globally, that is, all occurrences.
⁄e Evaluate the right side as an expression.
Wildcards and Repetitions:
. Match any character
\w Match "word" character (alphanumeric plus "_")
\W Match non-word character
\s Match whitespace character
\S Match non-whitespace character
\d Match digit character
\D Match non-digit character
\t Match tab
\n Match newline
\r Match return
\f Match formfeed
\a Match alarm (bell, beep, etc)
\e Match escape
\021 Match octal char ( in this case 21 octal)
\xf0 Match hex char ( in this case f0 hexidecimal)
* Match 0 or more times
+ Match 1 or more times
? Match 1 or 0 times
{n} Match exactly n times
{n,} Match at least n times
{n,m} Match at least n but not more than m times
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