Regular Expression Examples

Description	Regexp (GNU Extended Grep dialect - "grep -E" or "egrep")	Matches these lines	Does not match these lines	Comments
A specific word	Hello	Hello Hello there! Hello, World! He said, "Hello James", in a very threatening tone	Hi there Hell of a Day h el lo	This will match "Hello" anywhere on the line, but not permit any variations, such as spaces in the word or UPPER-/lower-case changes.
A specific word with nothing else on the line	^Hello$	Hello	Hello there! Hello, World! He said, "Hello James", in a very threatening tone Hi there Hell of a Day h el lo
5-character line	^.....$	rouge green Ho-ho	Yellow long line tiny 12-45-78	The anchor characters prevent extra characters from existing between the five characters and the start and end of the line.
Lines that start with a vowel	^[AEIOUYaeiouy]	Allo Everything Energy Under Yellow everything	Hello White 4164915050 Grinch	The character class includes both UPPERCASE and lowercase letters. You could instead use the option (specific to the tool you're using) to ignore case; for example, ''-i'' for grep or ''/I'' for findstr.
Lines that end in a punctuation mark	[[:punct:]]$	Hello there! Thanks. What do you think?	Hello there 416-491-5050 New Year greetings
Lines where the 3rd character is the letter "J"	^..J	S J 94723 N J 244325 N3J 2R6	JKLM Just Kidding	This pattern is anchored to the front of the line, and maches any characters in the first two positions followed by the letter 'J' (uppercase only) in the third position.
Lines that have fields separated by colons, where the third field is the number with four or more digits.	^[^:]*:[^:]*:[[:digit:]]{4,}:	jdoe:x:1007:1000:J. Doe:/home/jdoe:/usr/bin/bash rdoe:x:12425:1000:R. Doe:/home/rdoe:/usr/bin/bash	httpd:x:80:80:Apache HTTP server:/dev/null:/bin/false	The pattern [^:]* will match zero or more characters that are not colons, or in other words, the contents of one field. If you use this pattern to search the Linux file /etc/passwd, you should see only regular user accounts, since system accounts have user IDs (in the third field) that are three digits or less.
An integer	^[-+]?[[:digit:]]+$	+15 -2 720 1440 1280 1920 000 012	+ 4 3.14 0x47 $1.13 $4 123,456	This looks for lines that start with a + or - (optional), then contain digits.
A decimal number	^[-+]?[[:digit:]]+\.?[[:digit:]]*$	+3.14 42 -1000.0 +212 +36.7 42.00 3.333333333 0.976	.976 +-200 1.1.1.1 13.4.7	This will match lines that start with + or - (optional), then contain digits, then optionally contain a decimal point followed by zero or more additional digits.
A Canadian Postal Code	^[ABCEGHJKLMNPRSTVXY][0-9][ABCEGHJKLMNPRSTVWXYZ] ?[0-9][ABCEGHJKLMNPRSTVWXYZ][0-9]$	H0H 0H0 M3C 1L2 K1A 0A2 T2G 0P3 V8W 9W2 R3B 0N2 M2J2X5 M5S 2C6	POB 1L0 90210 MN4 2R6	A Canadian postal code alternates between letters and digits: A9A 9A9. The first letter must be one of ABCEGHJKLMNPRSTVXY and the remaining letters must be one of ABCEGHJKLMNPRSTVXY.
Phone Numbers (Canada/US)	^[^+[:digit:]]*(\+?1)?[^+[:digit:]]*[[2-9]]([^+[:digit:]]*[[0-9]]){9}[^+[:digit:]]*$	(416) 967-1111 +1 416-736-3636 416-439-0000	+65 6896 2391 555-1212	A Canadian/US phone number consists of a 3-digit Area Code (which may not start with 0 or 1) and a 10-digit local number consisting of an exchange (3 digits) and a line (4 digits). The country code for Canada and the US is 1, so the number may be preceeded by +1 or 1. Area codes are sometimes contained in parenthesis, and dashes or spaces are sometimes used as separators.
IP Address (IPv4 dotted quad)	`^((25[0-5]	2[0-4][0-9]	1[0-9][0-9]	[1-9][0-9]
Private IP Address	`^(10.(25[0-5]	2[0-4][0-9]	1[0-9][0-9]	[1-9][0-9]