> Unfortunately, this means that the behavior of a shell program cannot be known statically: a simple grep $PWD -in ~/.*shrc This is a weird claim. Every progr

> Unfortunately, this means that the behavior of a shell program cannot be known statically: a simple grep $PWD -in ~/.*shrc This is a weird claim. Every program's bahavior depends on its inputs in the general case. If you want to process static input you can do that using the shell. If your program should work on external inputs you cannot statically determine its output regardless of the language.