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

const regex = />(?P<Time>.*)\s+(?P<DeviceIPAddress>\d{1,3}.\d{1,3}.\d{1,3}.\d{1,3})\s+date=(?P<Date>.*)\s+time=(?:\d+\W+\d+\W+\d+)\s+devname=(?<DeviceName>.*)\s+devid=(?P<DeviceID>\w+)\s+logid=(?:\d+)\s+type=(?P<LogType>\w+)\s+subtype=(?P<SubType>\w+)\s+level=(?P<Status>\w+)\s+vd=(?P<User>\w+)\s+logdesc=[\W+](?P<Message>.*)[\W+]\s+session_id=(?P<Session_ID>\w+)\s+policyid=(?:\d+)\s+srcip=(?P<SourceIP>\d{1,3}.\d{1,3}.\d{1,3}.\d{1,3})\s+srcport=(?P<SourcePort>\d+)\s+dstip=(?P<DestinationIP>\d{1,3}.\d{1,3}.\d{1,3}.\d{1,3})\s+dstport=(?P<DestinationPort>\d+)\s+action=(?P<Action>\w+)\s+alert=(?:\d+)\s+desc=[\W+](?P<Description>.*)[\W+]\s+msg=[\W+](?P<msg>.*)[\W+]/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('>(?P<Time>.*)\\s+(?P<DeviceIPAddress>\\d{1,3}.\\d{1,3}.\\d{1,3}.\\d{1,3})\\s+date=(?P<Date>.*)\\s+time=(?:\\d+\\W+\\d+\\W+\\d+)\\s+devname=(?<DeviceName>.*)\\s+devid=(?P<DeviceID>\\w+)\\s+logid=(?:\\d+)\\s+type=(?P<LogType>\\w+)\\s+subtype=(?P<SubType>\\w+)\\s+level=(?P<Status>\\w+)\\s+vd=(?P<User>\\w+)\\s+logdesc=[\\W+](?P<Message>.*)[\\W+]\\s+session_id=(?P<Session_ID>\\w+)\\s+policyid=(?:\\d+)\\s+srcip=(?P<SourceIP>\\d{1,3}.\\d{1,3}.\\d{1,3}.\\d{1,3})\\s+srcport=(?P<SourcePort>\\d+)\\s+dstip=(?P<DestinationIP>\\d{1,3}.\\d{1,3}.\\d{1,3}.\\d{1,3})\\s+dstport=(?P<DestinationPort>\\d+)\\s+action=(?P<Action>\\w+)\\s+alert=(?:\\d+)\\s+desc=[\\W+](?P<Description>.*)[\\W+]\\s+msg=[\\W+](?P<msg>.*)[\\W+]', 'gm') const str = `<187>Oct 18 16:24:11 10.76.103.254 date=2020-10-18 time=16:18:44 devname=JAIPUR-FGT60D devid=FGT60D4615072349 logid=0105048038 type=event subtype=wad level=error vd=root logdesc="SSL Fatal Alert received" session_id=3eb37145 policyid=0 srcip=222.186.136.150 srcport=54221 dstip=59.111.181.52 dstport=443 action=receive alert=2 desc="bad certificate" msg="SSL Alert received"`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions