- int main(); set Boolean and decide which function to enter
- void run(); check the inputline if there have pipes run connectpipe, else run _run with argument nopipe
- void separate(char *commands); seperate the inputline into each string and store in command
- void prompt(); write the initial line
- void interact(); run prompt() and run()
- void connectpipe(); check the amount of pipe and separate it to three kind of argument and run _run
- void _run(pipekind kind); throw the pipekind and command to execute, after execute replace the co mmand to next command
- void redirect(); check which sign it is and run the correspond function
- void redirect_in(size_t index); redirect in
- void redirect_out(size_t index); redirect out
- void redirect_err(size_t index); redirect error
- void execute(char **command, pipekind kind); use two pipe to get previous output and pass to current input and run execvp after using pipe close it to end the process
- void erase(char **command); free
- bool eof(int c); end