Imagine that you want to use Molecule to test an Ansible role with a not default value. That's just one off test, so adjusting molecule configuration in the converge.yml (or similar) file is not required. It's not very prominent in documentation, but you can pass Ansible variables after "--" (minus, minus) in the molecule commend. For example:
molecule converge -- -e "role_new_var=true"
Imagine that you need to try to find a word in hundreds files located in a plenty of subfolders. grep -Rc might be a good candidate, but it's going to print the list of all files and the word is in just a handful of them. To make the output better grep can be joined with awk (and in the example below with zsh).
I needed to find an example of sqlcmd command usage in my Ansible roles collection. I used the power of ZSH globbing (a few other examples can be found here and in other places) to limit search to yml file only. ZSH "**" pattern is also a nice replacement to the grep "--recursive"option. In awk the "-F" flag replaces the standard delimiter with the ":" character and prints only lines with second field not equal to zero.
grep -c sqlcmd **/*.yml | awk -F":" ' ($2 != 0 ){print $0}'