Wondering how you can replace text content in every file using regex?
Just create and alias using your shell. Im my case it will be fish alias:
Add to your ~/.config/fish/config.fish this line:
alias replace "perl -p -i -e $argv"
and here you go!
~ $ replace 's/hello/goobye/g' *.md
BTW! Hope you have perl installed. I have ;)