Regular Expressions

[]

[]

Match single value in range that is listed inside the bracket.

-

Used as range separator. To search, must be first in list

^

Matches the starting position within the line

[^ ]

Matches a single character that is not contained within the brackets

$

Matches last character. Must be at end of the expression

.

Match any character in position

\d

Matches any single decimal digit; this is equivalent to the class [0-9].

\D

Matches any single non-digit character; this is equivalent to the class [^0-9].

\s

Matches any single whitespace character; this is equivalent to the class [\t\n\r\f\v].

\S

Matches any single non-whitespace character; this is equivalent to the class [^ \t\n\r\f\v].

\w

Matches any single alphanumeric character; this is equivalent to the class [a-zA-Z0-9_].

\W

Matches any single non-alphanumeric character; this is equivalent to the class [^a-zA-Z0-9_].

*

Match previous character 0 or more times (lo*se) 🡪 lse, loose, looose

+

Match previous character 1 or more times (lo+se) 🡪 lose, loose, loose

?

Match previous character 1 or 0 times (lo?se) 🡪 lse, lose

{X}

Match previous character exactly x times

{x,y}

Match at least x, but no more than y (ba{1,4}t) 🡪 bat, baat, baaat, baaaat

{x,}

Match at least x or more times

()

grouping, seperaed by |

(?:

Non capturing group

\

Escape

/

Delimiter

|

Alteration or logical OR

\<

Match beginning of word

\>

Match the end of the word

\n

New line

\r

Carriage return

\t

tab

[[:alnum:]]

Alphanumeric characters

[[:alpha:]]

Alphabetic characters

[[:blank:]]

Blank characters, such as space and tab

[[:cntrl:]]

Control characters. In ASCII, these characters have octal codes 000 - 037 and 177 (DEL)

[[:digit:]]

Digits: 0-9

[[:graph:]]

Graphical characters: '[[:alnum:]]' and '[[:punct:]]'

[[:lower:]]

lower-case letters

[[:print:]]

Printable characters: '[[:alnum:]]', '[[:punct:]]', and space

[[:punct:]]

Punctuation characters

[[:space:]]

Space characters, including tab, newline, vertical tab, form feed, carriage return, and space

[[:upper:]]

Upper-case letters

[[:xdigit:]]

Hexadecimal digits