Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gm

Test String

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:))|([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|((:[0-9A-Fa-f]{1,4}){1,6})|:)|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)(\\.(25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]?\\d)){3}))|:)))"; final String string = "1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000\n" + " link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00\n" + " inet 127.0.0.1/8 scope host lo\n" + " valid_lft forever preferred_lft forever\n" + " inet6 ::1/128 scope host \n" + " valid_lft forever preferred_lft forever\n" + "2: enp4s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000\n" + " link/ether 00:17:31:f1:98:3c brd ff:ff:ff:ff:ff:ff\n" + "3: enp4s0f1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000\n" + " link/ether 00:17:31:f1:98:3d brd ff:ff:ff:ff:ff:ff\n" + "4: enp5s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000\n" + " link/ether 00:27:9e:b5:e6:da brd ff:ff:ff:ff:ff:ff\n" + " inet 5.2.14.1/29 brd 5.2.1.255 scope global noprefixroute enp5s0f0\n" + " valid_lft forever preferred_lft forever\n" + " inet6 fe80::5473:d653:a319:3d25/64 scope link noprefixroute \n" + " valid_lft forever preferred_lft forever\n" + "5: enp5s0f1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000\n" + " link/ether 00:26:9e:b5:e6:db brd ff:ff:ff:ff:ff:ff\n" + "27: ip_vti0@NONE: <NOARP> mtu 1480 qdisc noop state DOWN group default qlen 1000\n" + " link/ipip 0.0.0.0 brd 0.0.0.0\n" + "38: tunl0@NONE: <NOARP> mtu 1480 qdisc noop state DOWN group default qlen 1000\n" + " link/ipip 0.0.0.0 brd 0.0.0.0\n" + "50: tap0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 100\n" + " link/ether ea:04:cd:c5:81:fa brd ff:ff:ff:ff:ff:ff\n" + " inet 10.1.128.2/21 brd 10.1.135.255 scope global tap0\n" + " valid_lft forever preferred_lft forever\n" + " inet6 fe80::e804:cdff:fec5:81fa/64 scope link \n" + " valid_lft forever preferred_lft forever\n" + "fe80:0000:0000:0000:0204:61ff:fe9d:f156 // full form of IPv6\n" + "fe80:0:0:0:204:61ff:fe9d:f156 // drop leading zeroes\n" + "fe80::204:61ff:fe9d:f156 // collapse multiple zeroes to :: in the IPv6 address\n" + "fe80:0000:0000:0000:0204:61ff:254.157.241.86 // IPv4 dotted quad at the end\n" + "fe80:0:0:0:0204:61ff:254.157.241.86 // drop leading zeroes, IPv4 dotted quad at the end\n" + "fe80::204:61ff:254.157.241.86 // dotted quad at the end, multiple zeroes collapsed\n\n" + "In addition, the regular expression matches these IPv6 forms:\n\n" + "::1 // localhost\n" + "fe80:: // link-local prefix\n" + "2001:: // global unicast prefix\n\n\n\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html