Why is an environmental variable not expanded in one of my machine but work on the other in Vim?

Question

I use two Macs and use the same ~/.vimrc file, which is stored at Dropbox, and add a symbolic link to it from within both computers at the same location, ~/.vimrc. So I don't think there is any difference whatsoever between the two computer's ~/.vimrc file.

However, when I try to call :tabnew $R from within one computer's MacVim application, the environmental variable is not expanded correctly. The command works on my other computer, and I set $R to ~/r in both of my Macs.

So what does prevent one from being expanded but nonetheless it works on the other? Even echo $R not working on the computer...

The official doc implies that I don't need to set any configuration to properly expand the environmental variable. Also, the environmental variable correctly is expanded in my Terminal.

Is there anything that I'm missing?

Answer 1

I finally got the reason it prevented environment variables from being expanded is that I switched to zsh shell, and it doesn't load those environment variables defined in ~/.zshrc when MacVim is launched. When I used bash shell, I defined all of those variables in ~/.bash_profile.

The solution is to define those variables in ~/.zshenv, not ~/.zshrc. I suspect that the MacVim is assumed to be launched as a shell script, and when a command is executed as a shell script in zsh, only ~/.zshenv is loaded.

Answer 2

If even echo $R is not working, it means the environment variable R simply is not defined on that machine, so there's also nothing to expand in your .vimrc.