Here is how to change the roor login for centOS.

# ssh root@216.xx.xx.xx -p22

Run the passwd command

# passwd
Changing password for user root.
New password:
Confirm password:
Password changed

How to secure copy a file from remote server to to local directory:
/home/user/file.txt = remote file
/home/user/Desktop/ = path to copy to local system

# scp -r user@remote.server.com:/home/user/file.txt /home/user/Desktop/

-r Recursively copy entire directories

What if the port is on 2243?

Use:

# scp -P2243 -r user@remote.server.com:/home/user/file.txt /home/user/Desktop/

# scp -P -r user@remote.server.com:/home/user/file.txt /home/user/Desktop/

-P port Specifies the port to connect to on the remote host. Note that this option is written with a capital ‘P’, because -p is already reserved for preserving the times and modes of the file in rcp(1).

-p Preserves modification times, access times, and modes from the original file.

Copy from local to remote:

# scp -P 22 file.txt root@192.168.1.1:/vmfs/volumes/datastore1/ISO

Recently, I had to find a connection script for mysql as the clients programmer had gone away. I knew the database username and here is the grep command that found it.

# cd /var/www/vhosts/domain.com/httpdocs
# grep -r 'database username' *

* Where database username is the actulay database username in the plesk database

Source: http://www.cyberciti.biz/faq/linux-unix-nginx-too-many-open-files/

options are you can disable nginx or change the configuration. What is Does?

nginx comes with plesk, it serves the static files and hands .php requests off to apache

you can also disable nginx by running:

# /usr/local/psa/admin/bin/nginxmgr -d