The fourth bird questions

The fourth bird answers

• Regex to match 1 or 2 occurrences
• Regex : how to optional capture a group
• How to capture unknown number of words in between a negative lookbehind catch term regex?
• How to remove control characters except new line? (C#)
• How to get all the matches for a repeated group in a RegExp in JavaScript?
• Regex for detecting arbitrary alphanumerics (with possible special characters in between) that are *not* purely alphabetical
• filemtime returns same value before and after modification of file
• How to match a string (?,?,?) in Java
• Place a dot before a letter
• Positive Lookbehind greedy