Originally Posted by ilesterg
would like to change career to a Linux professional.
"Linux Professional" is a rather vague term.
I'm an internet infrastructure admin, primarily admin for LAMP stacks plus associated networking, routing, switches, load-balancers, Citrix XenServer, etc. As that's the "day job", that makes me a "Linux Professional"
I don't claim to know much about Linux on the desktop (other than that I think it's a bad idea for a corporate desktop). That makes me a "Linux Amateur!"
If you've experience of Oracle applications then consider specialising in the Database Administrator area, as companies get more and more in to "big data" the demand for this skillset will increase.