The fourth bird questions

The fourth bird answers

• Python regex matching group with multi-layer conditions
• RegEx for combining multiple sequences
• Regular expression to identify groups
• Python Regex Sentence Finder-Want to Ignore "a.m."
• Regex expression to check if first and last char of set are different
• Perl regex capture each character as one group
• Single out everything after last occurence of a 10 number string
• Regex to match an aws arn
• How to update a multichracter delimited field in a file in bash?
• RegEx pattern to not allow special character except underscore