Projectile search only part of the project

Question

When using emacs Projectile and helm-projectile, I am used to search for text inside the whole project. However is there a way to search only part of the project?

Something like:

• search inside a subfolder only
• search while excluding a subfolder

Answer 1

For now I am using rgrep, which prompts for a string and a directory to find.

I would be happy to hear about an equivalent solution using ag, and I should mention I haven't yet dug into the link from @goromlagche (https://github.com/ggreer/the_silver_searcher#emacs).