This is a simple shell that can read and interpret commands(no more than 10 parameters), also has the capability to deal with many kinds of inputs.
functions:
simple_sh.c: the main function, run() function(run the loop to access user's input) and generate_pipe() function(recursive function, which can pipe and fork).
prompt.c: prompt function, which shows the prompt for the user.
interpret_input.c: interpret user's input and translate it to parameters.
add_history.c: add items to history list.
built_in: deal with the built_in commands(exit, cd , and history).
s2i.c: translate a string into an integer.
clear_history: clear the history list.
interpret_line: interpret a line with the delimtor.
builtin_pipe: deal with the builtin commands in a pipe situation.
and the header: simple_sh.h, which defines all the functions and macro definitions
Makefile: make the binary file to generate and clean it.