for me it was linux academy (paid by my employer of the time) and getting red hat certified (rhcsa). in order to get rhcsa certified i had to study and learn a

for me it was linux academy (paid by my employer of the time) and getting red hat certified (rhcsa). in order to get rhcsa certified i had to study and learn all of those little details about linux that i had only skimmed previously, and learn some things that i didn't even knew existed (ex: filesystems acl). Getting Red Hat certified definitely made me a better sysadmin and a devops engineer with a stronger linux background. edit: since moving on from that employer i'm paying for linuxacademy myself, although nowadays it's not clear what's going to happen when ther merger with acloudguru will be fully done.