diff --git a/docs/books/sed_awk_grep/1_regular_expressions_vs_wildcards.md b/docs/books/sed_awk_grep/1_regular_expressions_vs_wildcards.md
index 3eea8b6ae4..26df8aa83c 100644
--- a/docs/books/sed_awk_grep/1_regular_expressions_vs_wildcards.md
+++ b/docs/books/sed_awk_grep/1_regular_expressions_vs_wildcards.md
@@ -154,4 +154,5 @@ Many websites exist for practicing regular expression skills online, such as:
 * [regexr](https://regexr.com/)
 * [regelearn](https://regexlearn.com/)
 * [coding](https://coding.tools/regex-tester)
+- [cyrilex](https://extendsclass.com/regex-tester.html)