Handy PERL regular expressions

Pattern	Description
/a./	The . matches any singe character except newline(\n)  eg.ab a
/[abcde]/	Matches a sting containing any one of the first five letters a lowercase alphabet eg.dog box
/[aeiouAEIOU]/	Matches any of the five vowels in either lower or uppercase eg.India egg
/[0123456789]/	Match if any single digit is present  eg. 0 3 41 100
/[0-9]/	Matches any single digit like the above                0 3
/[0-9\-]/	Match 0-9, or minus                        - 0 3
/[a-z0-9]/	Match any single lowercase letter or digit            a 0 9
/[a-zA-Z0-9_]/	Match any single letter, digit, or underscore            a X 9 _
/[^0-9]/	Match any single non-digit                    a
/[^aeiouAEIOU]	Match any single non-vowel                    M N L
/[^\^]/	Match single character except an up-arrow            M N L
/[\da-fA-F]/	Match one hex digit
/fo+ba?r/	Matches an f followed by one or more o's followed by a b, followed by an optional a, followed by an r.
s/x+/boom/	Always replaces all consecutive x's with boom (resulting in fred boom barney), rather than just one or two x's, even though a shorter set of x's would also match the same regular expression. ie. $_ = "fred xxxxxxxxxx barney";
/x{5,10}/	Matches five to ten x's
/x{5,}/	Means five or more in this case
/x{5}/	Means "exactly this many" (five x's).
/x{0,5}/	Matches five or less x's
/a.{5}b/	Matches the letter a separated from the letter b by any five non-newline characters at any point in the string.
/a.*?c.*d/	matches the fewest characters between the a and c, not the most characters.
/oracle/	True if oracle matches. Note this will also match XoracleY
/\boracle\b/	True if only oracle matches
/ora\b/	True for anything that ends with ora, but fails for oracle. The \b is the word boundary.
/\bo/	True for oracle oozie operator, basically anything that begins with o
/\bora/	True only for anything that begins with ora
/^ora/	True only if it begins with ora, orc will fail
/^(o|h)/	True for only words begining with o or h
/^x|y/	Matches x at the beginning of line, or y anywhere
/abc*/	Matches ab, abc, abcc, abccc, abcccc, cab, zabc
/a|bc|d/	Matches a, bc, d, but not xyz, xbz
/(a|b)(c|d)/	Matches ac, ad, bc, or bd
/(song|blue)bird/	Matches songbird or bluebird
if (<STDIN> =~ /^y/i)	True if the input begin with a y
s/foo/bar/g	Replaces foo with bar in the string $_