If you want to check how much disk space your server has, how much disk has been used and how much free disk space is left on your Linux server, here is simple command for that.
Login to your server as root via SSH and run following command.
df -h
This will show size, Used, Available, File system mount points.
If you want to check disk usage summery of any particular directory, say /home use below command:
df -h /home
