wish stands for 'Wisconsin Shell" it is a simple UNIX like shell, that I will built as part of my study for this OS course.

the whole thing is built around this

struct program{
    char* name;
    uint argc;
    char** argv;

    /**
     * @brief 
     * if null output should be written into the standard output stream.
     * other wise the string will be considered as the file name to which the program
     * output should be redirected.
     */
    char* outstream; 
};

struct program is an abstraction of what the user of the shell want to do it could be a built-in function of the shell or a 3rd party binaries. for example, if the user typed

ls -l -a > out.txt

this will be converted into a program struct with

name = ls
argc = 2
argv = {-l, -a}
outstream = out.txt

parse one command line at a time, it builds a list of programs (the abstraction mentioned above) each program will run in a seprate process in parallel to the others, it works in major steps

• parse for the special operators supported by the shell ex "& is the parallel execution operator" and "> output redirection operator"
  • it starts by spliting the command into sub commands around the '&' operator
  • then start looking for the ">" operator if exist within each sub command
• build a program (abstraction mentioned above) from the individual sub commands
  • extract the program name
  • extract the arguments

will carry on the logic to exceute built in functions and 3rd party binaries. [not implemented yet]

• interactive mode.
• batch mode.
• support search path.
• enable the user to concatenate more search directories into the current search path.
• support built in commands.
• support redirection for other programs.
• support redirection for build in commands.
• support multiple level of redirections [if this is possible].
• running parallel commands.
• handling parsing errors and other errors that the shell should be responsible for.
• provide debug mode for detailed logs.