Whether to use dashes or underscores in a URL depends on which part of the URL you are changing as well as your purpose. It's not always a simple answer.
URL Best Practices: Analysing The Effect Of Dash And Underscore
Dash - Wikipedia
Hyphen Vs. Underscore in URL: Which is Best for SEO
URL Best Practices: Analysing The Effect Of Dash And Underscore
New Poll: Hyphens, Underscores, or camelCase?
Dash or Underscore in URL for SEO (Finally Answered) ‐ sitecentre®
Why do dashes in URLs give better Google page rankings than underscores? - Quora
When to Use the Em Dash—and the En Dash and 3-Em Dash
Best WordPress Permalink Structure for SEO - MediaOne
Dash or Underscore in URL for SEO (Finally Answered) ‐ sitecentre®
Dash or Underscore in URL for SEO (Finally Answered) ‐ sitecentre®
Dash - Wikipedia
All of us can relate with this one : r/ProgrammerHumor
