corrected typo, simpler solution for an exercise

Author: learnbyexample

README.md

@@ -46,7 +46,7 @@ For the web version of the book, visit https://learnbyexample.github.io/learn_gn
 
 ⚠️ ⚠️ Please DO NOT submit pull requests. Main reason being any modification requires changes in multiple places.
 
-I would highly appreciate if you'd let me know how you felt about this book. It could be anything from a simple thank you, pointing out a typo, mistakes in code snippets, which aspects of the book worked for you (or didn't!) and so on. Reader feedback is essential and especially so for self-published authors.
+I would highly appreciate it if you'd let me know how you felt about this book. It could be anything from a simple thank you, pointing out a typo, mistakes in code snippets, which aspects of the book worked for you (or didn't!) and so on. Reader feedback is essential and especially so for self-published authors.
 
 You can reach me via:
 

exercises/Exercise_solutions.md

@@ -533,7 +533,7 @@ $ echo "$s" | sed -E 's/\b([0-9]+)\1+\b/\1/g'
 
 ```bash
 $ ip='wow:Good:2_two.five: hi-2 bye kite.777:water.'
-$ echo "$ip" | sed -E 's/(\w+)[:.](\w+[:.])+/\1/g'
+$ echo "$ip" | sed -E 's/([:.]\w*)+//g'
 wow hi-2 bye kite
 ```