⚠️ NOTE: If you have any questions regarding the content presented below, feel free to post them here. I will be happy to help anyway I can! Regex is a big passion of mine and I look forward to hearing from you. 😁
POSIX is a special kind of character class bracket expression. It uses lower case references and functions similar to the metacharacters we I demonstrated earlier.
Here are a few examples:
[[:alnum:]] =~ Alphanumeric characters
[[:alpha:]] =~ Alphabetic characters
[[:digit:]] =~ Digits
[[:ascii:]] =~ ASCII characters
[[:punct:]] =~ Punctuation and symbols
[[:lower:]] =~ Lowercase letters
[[:space:]] =~ All whitespace including line breaks
[[:cntrl:]] =~ Control characters
NOTE: The Portable Operating System Interface is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems.