I think I opened an unsafe unix exe file! Can anyone tell me what this file might've done? I was downloading a crack file for premier 2019 pro cc as something went wrong with my subscription and now I don't have premier, so when I opened the dmg. It showed an installer and I went through with the installation...(stupidly) nothing changed, but I am scared that I might have caused an issue to my computer.

How can I make sure that my system didn’t get infected by malware?

PS: I still have the .dmg on my computer in case I need it to see if damage can be reversed. 

I don't know how to read the script or anything and I am just worried I might have given someone access to my personal and private information or might have caused an issue for may computer.
Without analyzing the scripts etc you run nobody can tell what (if anything) happened to your computer. To recover the best course of action is to restore from a backup made before you opened the DMG.