mini-shell-racoon

• work on linux and macos:
  install: make install

this project impliment the minimal parts of a shell

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• moving in out directory

• evaluting user input such as -> "$USER" -> jemartel

• executing local command such as ./minishell

• executing absolute command such as /bin/sh

• executing command without saying the path

• redirecting input with "input rediction" with the symbol "<"

• redirecting output with "input rediction" with the symbol ">"

• redirecting output and adding to the end with "append rediction" with the symbol ">>"

• redirecting input with "input 'here-redicetion' " with the symbol "<<"

• the shell command of (env,export,echo,exit,cd)

• return value of the lass process passed down the execution from subprocess

• piping elements from one command to the other "ls | wc | wc"

Program structure

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• parsing: "creates tokens from the base string tha come from readline" then if an error occcure a this stage it will prompt an error and display the display it to screens the tokens are place in a doubly linklist "(yes its not a tree)" each token in a the list will be typed "its a number" according to previous assumpitons

• jobs: a doubly linklist that is create from the previous list; each jobs as fews composents: such as the arguments for a command if there is a commands if there redirecton ther will be an list:(a doubly link list) if there a error somewhere everything before will be deleted

• evalution: each string passed down the pipeline will be converted to what it should be element prefixed with with a $ in and out of a string will be 'expanded' otherwise the value with the $ before stay the same without the ' the 'quoting can be nested the first seen do the behavior' the evalution part of the program is self standing and can be use in any other project with minimal change

• execution: at this stage the program will try to do rediction < > >> but not << since its done 'in evalution part' any errror will bail an early exit and not execute anything last part is trying to see if the arguments is an executable or otherwise EVERYTHING tha is not readline in a subprocess will be deleted in an errors or not

tour of the struggle that we had during the project

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• mini-shell-racoon/executing/find_part.c

  Line 68 in e8d0e5a

  void delete_builtin(t_jobs *job, t_pipe *pipes, const char *local)

  since we are required to free all the memory forking is quiete tricky to keep track of since we use readline give some level of overhead in term of memory usage: to get this checked i made program able to be run without readline wich "-c" wich allow us to see how much memory the program is use without it... this feature can also be use to make unit test.

• mini-shell-racoon/parsing/parsing.c

  Line 16 in e8d0e5a

  void handle_pipes(t_pipe *pipes, int status)

• mini-shell-racoon/executing/fd.c

  Line 15 in e8d0e5a

  void handle_fd(t_pipe *pipes)

  handling correctly pipes was quiete a challenge since i could not find alot of example on the subject that could fit in the project

• mini-shell-racoon/jobs/jobs_lst.c

  Line 60 in e8d0e5a

  char **jobs_lst_creator(t_dlist *lst, t_dlist **lst_head)

  since i took the path of not creating a binary tree i had to manualy figure out the path of each comand in any order the complexity come from the fact that redirection can take place before the command and after the command and argument are in the middle example "< main.c cat -e < utils.c" the argument are cat -e and the other tokens are use as redirection

• mini-shell-racoon/eval/eval.c

  Line 75 in e8d0e5a

  char *eval_line(char *str, char *output, int lon, int type)

  evalution can get a bit messy since you can handle many type of token than can be followed one after the other such as 'hello'"word"github or '$USER'"$USER"$USER or trying or having an random quote in the other type of quote " 'hello" or the way around what should the evalution return when the enviroment does not have the value a NULL ptr? or simply a empty string? i choose empty string since you incrimentaly make a string the memory handling get wild you have to keep track of the base string and not free it while also keeping track of the previous part: i solved most of thoses overhead with

• mini-shell-racoon/eval/eval_util.c

  Line 46 in e8d0e5a

  char *lazy_join(char *first, char *second)

want to know more on how to build a shell?

- https://github.com/csabagabor/Basic-Shell-implementation-in-C/blob/a176b00b5f03027882ea1f7ae6c7f01f697cc328/shell.c#L83
- https://githubmemory.com/repo/gleal42/42_Minishell
- https://www.cs.purdue.edu/homes/grr/SystemsProgrammingBook/Book/Chapter5-WritingYourOwnShell.pdf
- https://www.notion.so/Minishell-Materials-7bbd45a806e04395ab578ca3f805806c