> > and common > Not even remotely. Real world code from numerous prominent open source projects begs to differ. Almost every random script I've opened in ran

> > and common > Not even remotely. Real world code from numerous prominent open source projects begs to differ. Almost every random script I've opened in random open source projects made use of unexported shell variables. Take a look at the source repositories of the Linux kernel, Git, coreutils, GCC, LLVM, CMake, GDB, cURL, OpenSSL, Firefox, Chromium, Vim, and tmux. It's so prevalent that I don't even know why I have to point this out.