nginx catch all

 server {

return 444;

}

du -sh only given parition (ex root)

 du -h -x -d 1 /

-x = --one-file-system skip directories on different file system

-d = maximum depth

-h = human readable 

/ = partition

OpenSSL check SSL cli

 OpenSSL check SSL: 

openssl s_client -showcerts -connect server.domain.com:465 smtp

OpenSSL check SSL expiration etc:

openssl s_client -showcerts -connect server.domain.com:465 | openssl x509 

journalctl read logs from given service

journalctl --no-pager --unit=nginx