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

/
/
g

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression. sed -E 's/https?:\\/\\/\Kexample\.com/abc.host.prov.com/g;t' <<< "<img class=\"aligncenter wp-image-27283 size-large\" src=\"http://example.com/wp-content/uploads/2017/04/image-3-1024x1024.jpeg\" alt=\"homemade chocolate recipe\" width=\"640\" height=\"640\" srcset=\"http://example.com/wp-content/uploads/2017/04/image-3-1024x1024.jpeg 1024w, http://example.com/wp-content/uploads/2017/04/image-3-300x300.jpeg 300w, http://example.com/wp-content/uploads/2017/04/image-3-768x768.jpeg 768w, http://example.com/wp-content/uploads/2017/04/image-3-696x696.jpeg 696w, http://example.com/wp-content/uploads/2017/04/image-3-1068x1068.jpeg 1068w, http://example.com/wp-content/uploads/2017/04/image-3-420x420.jpeg 420w, http://example.com/wp-content/uploads/2017/04/image-3-560x560.jpeg 560w, http://example.com/wp-content/uploads/2017/04/image-3.jpeg 1080w\" sizes=\"(max-width: 640px) 100vw, 640px\" />"

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 SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html