Question about "debug = xxx.stdout" / xxx.stdout_lines / xxx.stdout_lines[0]

Hi there,

I am new to Ansible and I am learning this toolkit. When I am dealing w/ the output, I find there are various ways to handle the variables. Some examples shows “debug = xxx.stdout”, Some examples mention “xxx.stdout_lines” and “xxx.stdout_lines[0]”. Is there anyone can share more info definition of these outputs and any whitepaper / tutorials to describe the details?

Thanks
Leon Lai