jgadelugo / simple_shell

SIMPLE SHELL

Description

Project 0x16 - Simple Shell - A simple UNIX command interpreter that executes commands read from the standard input or from a file. Based on the Bourne Shell.

List of Allowed Functions and System Calls

• access (man 2 access)
• chdir (man 2 chdir)
• close (man 2 close)
• closedir (man 3 closedir)
• execve (man 2 excve)
• exit (man 3 exit)
• _exit (man 2 _exit)
• fflush (man 3 fflush)
• fork (man 2 fork)
• free (man 3 free)
• getcwd (man 3 getcwd)
• getline (man 3 getline) - Bonus if not used
• isatty (man 3 isatty)
• kill (man 2 kill)
• malloc(man 3 malloc)
• open (man 2 open)
• opendir (man 3 opendir)
• perror (man 3 perror)
• read (man 2 read)
• readdir (man 3 readdir)
• signal (man 2 signal)
• stat (__xstat)(man 2 stat)
• lstat (__lxstat)(man 2 lstat)
• fstat (__fxstat)(man 2 fstat)
• strtok (man 3 strtok) - Bonus if not used
• wait (man 2 wait)
• waitpid (man 2 waitpid)
• wait3 (man 2 wait3)
• wait4 (man 2 wait4)
• write (man 2 write)

Installing

Compile:

gcc -Wall -Wextra -Werror -pedantic *.c -o hsh

Usage

./hsh
$ echo Hello World

cat testfile
echo Hello World
./hsh testfile
Hello World

Examples

cd:

$ cd directory/to/change/to

env:

$ env

setenv:

$ setenv VARIABLENAME VALUE

unsetenv:

$ unsetenv VARIABLENAME

exit:

$ exit 127

File Structure

0. my_shell.c - The main function for simple_shell

• int main(int argc, char **argv, char **envp) - main function, where program starts
• void my_error(char *command, int status, char *extra) - Custom error printing
• char *get_prog_name(char *name) - Gets the program name
• int linum(int add) - Gets current line number and/or add to it

1. env_ops0.c - Environmental variable functions

• char *get_env_val(char **, char*) - Gets the value of an env variable
• char **get_path(char **env) - Gets the path in a double char pointer
• char *find_path(char **path, char *command) - finds if a command exist in a path and returns the path
• char **get_env(void) - Get current environment as a malloc'd NULL
• char *get_full_command(char *path, char *command) - Gets the command with the correct path prepended

2. env_ops1.c - More environment variable functions

• char **do_env(char *add, char *delete) - Get the env, or add a variable, or delete a variable

3. ll_ops0.c - Linked list functions

• size_s list_len(list_s *h) - Gets size of a list_s linked list
• list_s *add_node(list_s **head, void *ptr) - Adds a new node at the beginning of a list_s linked list
• list_s *add_node_end(list_s **head, void *ptr) - Adds a new node at the end of a list_s linked list
• void free_list(list_s *head) - Frees list_s linked list

4. ll_ops1.c - More linked list functions

• void free_list_full(list_s *head) - Frees list_s linked list and all contained pointers
• list_s *get_node_at_index(list_s *head, unsigned int index) - Returns the nth node of a linked list
• list_s *insert_node_at_index(list_s **head, unsigned int idx, void *ptr) - Inserts a new node at a given position
• int delete_node_at_index(list_s **head, unsigned int index) - Deletes a node at a given position

5. ll_ops2.c - More linked list functions

• char **arrayify(list_s *head) - copy a char * linked list into a char **
• list_s listify(char **arr) - copy a char ** array into a malloc'd char * linked list
• void free_double_array(char **list) - Free a double char pointer

6. __ll_ops0.c - Linked List functions

• size_t __list_len(list_t *h) - Get size of a list_t linked list
• list_t *__add_node(list_t **head, void *ptr) - Adds a new node at the beginning of a list_t list
• list_t *__add_node_end(list_t **head, void *ptr) - Adds a new node at the end of a list_t list
• void __free_list(list_t *head) - Frees list_t linked list

7. __ll_ops1.c - More linked List functions

• void __free_list_full(list_t *head) - Frees list_t and all contained pointers
• list_t *__get_node_at_index(list_t *head, unsigned int index) - Returns nth node of a linked list
• list_t *__insert_node_at_index(list_t **head, unsigned int idx, void *ptr) - Inserts a new node at a given position
• int __delete_node_at_index(list_t **head, unsigned int index) - Deletes a node at a given position

8. str_ops0.c - String functions

• int _strcmp(char *s1, char *s2) - Compares two strings
• int _strlen(char *s) - Gets the length of a string
• int word_count(char *str, char *delim) - counts the number of words in a string separated by a delim
• char *_strcat(char *dest, char *src) - Concats two strings
• char *_strcpy(char *dest, char *src) - Copy src into dest

9. str_ops1.c - More string functions

• int _atoi(char *s) - Converts a string to an integer
• int sizeof_command(char **tokens, int place) - Gets the size a command separated by ;, &&, ||
• int _isdigit(int c) - Check for a digit (0 through 9)
• int has_newline(char *input) - checks for \n and returns the index
• void shiftbuffer(char *input, int newline_index, int filled) - shifts the buffer to the next command after

10. str_ops2.c - More string functions

• char *_reverse(char *str, int n) - Reverses the content of a string
• char *_itoa(int num) - Converts an integer base 10 to a string
• char *_memset(char *s, char b, int n) - memset function

11. my_exit.c - Memory and exit functions

• void *do_mem(size_t size, void *ptr) - Malloc, free or free all with a static record
• void do_exit(int fd, char *msg, int code) - Custo exit with error message, code and automatic memory cleanup

12. strtok_to_double_pointer.c - strtok function that returns double pointer

• void _free(char **list, int count) - Frees a double char pointer in case of error
• char **_strtok(char *str, char *delim) - Splits a string into an array of strings based on delimiters

13. _getline.c - getline function

• char *_getline2() - Reads 1024 characters from stdin and returns the string read
• ssize_t _getline(char **lineptr, size_t n, int stream) - Reads a number of chars from stdin and returns size read
• ssize_t else_handle_input(char *lineptr, int stream, char *input, int filled) - Handle buffer if it does not include \n or EOF

14. builtin_ops.c - functions for builtin commands

• char **get_builtins() - Create list of builtin functions
• void cd_builtin(char **tokens) - Executes cd function, changes directory
• int env_builtin(void) - lists environment
• int setenv_builtin(char **tokens) - Set an environment variable
• int unsetenv_builtin(char **tokens) - Unset an environment variable

15. file_ops.c - Prep input file to execute list of commands

• char *read_textfile(char *filename) - read text file and return as string

16. exec_ops0.c - Execute functions

• int exec_builtin(char **tokens, int bcase) - Execute function for builtins
• int check_access(char *comm, char *token) - Checks if path exists or if permission exists for command
• char *prep_execve(char *token) - preps command by checking current path and then the PATH for command
• int exec_nb(char **tokens) - Execute function for non builtins
• int search_ops(char **tokens) - search for ;, &&, || operators

17. exec_ops1.c - More execute functions

• int exec_single(char **tokens) - execute a single command
• char **get_next_commands(char **tokens) - Gets the tokens after the first &&, || or ;
• char **get_current_command(char **tokens) - Gets the command before && || or ;
• int execute(char **tokens) - Main execute funtion

Authors

• Jose Alvarez de Lugo
• William Dyrland-Marquis