This is a spreadsheet that summarizes the most popular Linux certifications.
In it, you’ll find:
How long each certification lasts
What exams you’ll have to pass in order to be certified
The approximate cost of training required to become certified
There are a lot of certifications, so here’s the perspective of Linux Training Academy Founder and Author, Jason Cannon: "I’m a fan of the distro-agnostic Linux Professional Institute LPIC-1 certification. However, if you know you’ll be primarily working with RedHat, the Red Hat Certified System Administrator (RHCSA) certification is a great place to start."
Being certified is just one step on one path along the way. And there are MANY paths that will take you where you want to go.