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

/
/
gmxXi

Test String

Code Generator

Language

Generated Code

$re = '/# ./configure parser ^(?: (?:configuring[[:space:]]for[[:space:]](.+)) | (?: checking[[:space:]] (?: (?:build|host) [[:space:]]system[[:space:]]type | how[[:space:]]to[[:space:]](.+?) | for[[:space:]](.+?) | whether[[:space:]](?:to[[:space:]])?(.+?) )[\.]{3} ) (?: [[:space:]]+ (?: $ | (?: (yes) | (no) | (?<!^)(.*)(?=$|\n) ) ) )?.* )$ # ^(?:(?:configuring[[:space:]]for[[:space:]](.+))|(?:checking[[:space:]](?:(?:build|host)[[:space:]]system[[:space:]]type|how[[:space:]]to[[:space:]](.+?)|for[[:space:]](.+?)|whether[[:space:]](?:to[[:space:]])?(.+?))[\.]{3})(?:[[:space:]]+(?:$|(?:(yes)|(no)|(?<!^)(.*)(?=$|\n))))?.*)$/mxXi'; $str = 'configuring for zsh 5.7.1-test-2 checking build system type... x86_64-apple-darwin17.7.0 checking host system type... x86_64-apple-darwin17.7.0 checking for gcc... gcc checking whether the C compiler works... yes checking for C compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking for special C compiler options needed for large files... no checking for _FILE_OFFSET_BITS value needed for large files... no checking how to run the C preprocessor... gcc -E checking for an ANSI C-conforming const... yes checking for gcc option to accept ANSI C... checking whether to use prototypes... yes checking for grep that handles long lines and -e... /usr/local/bin/ggrep checking for egrep... /usr/local/bin/ggrep -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking for size_t... yes checking for working alloca.h... yes'; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php