The following Shell script must return how many characters that are returned using list function (Is): Is | Operating system can: provide a framework for executing programs. share system resources (CPU, memory, disk) among programs and users. allow communication with devices(monitor, keyboard, network, etc.) and other programs, file, read from a file, open a file. O All of the above When bash is invoked, it first executes the commands in the system-wide startup file, usually located in /etc/csh.cshrc. O True False it is recommended to turn off the buffer mode before using fwrite, because: Buffer mode may return success even though write system call fails o It may cause unpredictable results All of the above o None of the above