Online installation of SQL Server package on LINUX:
Prerequisites:
- A machine (VM, physical, etc) with Linux installed
 - Red Hat Enterprise Linux (7.3 or 7.4)
 - The Working internet to install package of SQL Server 2017 onto your Linux machine.
 - Repo file creation
 - Installing package
 
Start Vm and Login to linux
Here im using root user:
Creating Repository File:
Here are link  from microsoft to get the detail on repo file
sudo curl -o /etc/yum.repos.d/mssql-server.repo https://packages.microsoft.com/config/rhel/7/mssql-server-2017.repo
--To check repo file 
#cat /etc/yum.repos.d/mssql-server.repo 
--To cleans up any cached packages in any enabled repository cache directory
#yum clean all
--update to the latest current version of package.It takes some time to update
#yum update
Install package online
#sudo yum install -y mssql-server
After installation completion following screen apprears:
At this time setup files are loaded successfully. You have to copy the line from above command output shown in dotted line. 
Configure installation of sql server:
#sudo /opt/mssql/bin/mssql-conf setup
Choose edition based on requirement, as I am testing I choose Evaluation edition
Enter password for SA user.
Now check the status of services
#systemctl status mssql-server.service
So installation is completed successfully
We can check by connecting, first we need ip address
#ifconfig 
Connect using SSMS:
Use ip address from above command output and username as SA with your given password.