added old posts from ghost

content/knowledge-base/regex-basics.md

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+date = '2022-09-04T15:43:06'
+draft = false
+title = 'Regex Basics'
+type = 'post'
+tags = ['Misc']
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+[just text:](#just-text) matches any string with the given text inside it  
+[^](#^) matches string that starts with the given text  
+[$](#$) matches string that ends with the given text  
+[*](#*) zero or more  
+[+](#+) one or more  
+[?](#?) zero or one  
+[{n}](#{n}) `n` occurrences  
+[a|b or [ab]](#OR-operator) a or b  
+[\\d](#\\d) matches a digit  
+[\\w](#\\w) matches a word character (alphanumeric plus underscore)  
+[\\s](#\\s) matches a whitespace character  
+[.](#.) matches any character  
+
+## Anchors
+### just text
+`abc` matches any string that has the text _abc_ in it
+### ^
+`^abc` matches any string that starts with _abc_
+### $
+`abc$` matches any string that ends with _abc_
+### exact match
+`^abc$` matches only the exact string _abc_
+
+## Quantifiers
+### *
+`abc*` matches any string containing _ab_ followed by any number of _c_ s
+### +
+`abc+` matches any string containing _ab_ followed by at least one _c_
+### ?
+`abc?` matches any string containing _ab_ followed by at the most one _c_
+### {n}
+`abc{2}` matches any string containing _ab_ followed by two _c_ s  
+`abc{2,}` matches any string containing _ab_ followed by two __or more__ _c_ s  
+`abc{2,5}` matches any string containing _ab_ followed by between two and five _c_ s  
+
+## OR operator
+`a|b` _a_ or _b_
+`[abc]` _a_ or _b_ or _c_
+
+## Character classes
+### \d
+`\d` matches any character in a string that is a digit
+`\D` matches any character that __isn't__ a digit
+### \w
+`\w` matches any character in a string that is a word character
+`\W` matches any character that __isn't__ a word character
+### \s
+`\s` matches any whitespace character in a string
+`\S` matches any __non__-whitespace character
+### .
+`.` matches any character in a string