function system(Command: PChar): Integer;
The Libc.System function call is the most convenient way to start an external application. It simply executes the given argument command as shell command.

system is a blocking function, which means it will not return until the child process has terminated. The result value is -1 or 127 if an error occurred. The value 127 has the special meaning that execve (used within the system function - a more detailed description follows) failed.

이것 참고하세요.^^