Update cheatsheets

tldr/regex

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+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# regex
+
+> Regular expressions (`regex`) are patterns used to match, search, and manipulate text.
+> Not a direct command, but syntax to be used with other commands.
+> More information: <https://cheatography.com/davechild/cheat-sheets/regular-expressions/>.
+
+- Match any single character:
+
+`.`
+
+- Match the start of a line:
+
+`^{{hello}}`
+
+- Match the end of a line:
+
+`{{world}}$`
+
+- Match zero or more repeated characters:
+
+`{{a}}*`
+
+- Match a set of characters:
+
+`[{{abc}}]`
+
+- Match a range of characters:
+
+`[{{a-z3-9}}]`
+
+- Match anything but the specified character:
+
+`[^{{a}}]`