SCP scp is always our friend.

scp -i /path/to/permission/file username@ec2.url:/path/to/remote/file /path/to/local/directory

Update on 2019-10-14. What if I need to copy files that need root access?

ssh -i /path/to/permission/file username@ec2.url "sudo cat /var/log/nginx/access.log" > ~/Downloads/access.log

img

Generally, if it is a log that could be printed out. Just print and save it to local.