Check if the DISPLAY variable is set in Linux environment

Most of the users have been getting Could not execute auto check for display colors using command /usr/bin/xdpyinfo. Check if the DISPLAY variable is set in Linux environment while checking requirement the oracle installations on  Linux 5.2 or later versions.

Below is the screenshot of the issue

I have tried plenty of options, even ignoring the pre-requisites.

Finally, i have fixed this issue through one Linux command

Steps to resolve this issue:

1) login into root user( su -l root)

2) execute this command xhost +SI:localuser:oracle

3) login to the oracle user

4) execute ./runInstaller

Now, it'll work fine.