which - examine $PATH to see which file will be executed
which a.out # Tells which a.out will be executed
The $PATH shell variable controls the MINIX search rules. If a command
a.out is given, the shell first tries to find an executable file in the
working directory. If that fails, it looks in various system directories,
such as /bin and /usr/bin. The which command makes the same search and
gives the absolute path of the program that will be chosen, followed by
other occurrences of the file name along the path.