The old guru I learned Linux from always said: "The bugs I've spent the longest time tracing down have always been caused by environment variables. It was only when I started checking them first, rather than last, that I felt competent as a sysadmin."
Truth is, you aren't going to get rid of them unless you make an operating system that doesn't have them (and good luck porting anything useful to it). This is poor advice, because it amounts to FUD -- those problems won't go away, but in telling people to avoid environment variables will quash their curiosity about them. This teaches people to only look to the environment last.
Truth is, you aren't going to get rid of them unless you make an operating system that doesn't have them (and good luck porting anything useful to it). This is poor advice, because it amounts to FUD -- those problems won't go away, but in telling people to avoid environment variables will quash their curiosity about them. This teaches people to only look to the environment last.