A simple UNIX command line interpreter(in C ) that reads and implements basic commands from user input.

All files compiled on Ubuntu 14.04 LTS with gcc 4.8.4

Clone repo: $ git clone https://github.com/KRLoyd/simple_shell.git

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

Run simple_shell:

$ ./hsh

A prompt will follow upon running ./hsh
Simple_shell is ready to take commands:
($)

Pipe a command into the hsh shell as follows: $ echo "ls -la" | ./hsh

The following built-in functions are available in our shell

• env
• exit

Functions found by traversing the environment variable PATH may also be executed. Examples of these functions:

• ls with or without arguments
• pwd
• touch

access (man 2 access)
execve (man 2 execve)
exit (man 3 exit)
fork (man 2 fork)
free (man 3 free)
fstat (man 2 fstat)
getline (man 3 getline)
malloc (man 3 malloc)
perror (man 3 perror)
strtok (man 3 strtok)
wait (man 2 wait)

shell.h - header file containing function prototypes, struct definitions, macros, standard libraries.

simple_shell - simple shell program that 1) checks if in interactice/noninteractice mode 2) prints prompt and waits for user input 3) splits user input into an array 4) prints prompt again if in interactice mode

execution - executes the command passed as a string

man_1_simple_shell - man page for our shell

PATH

• search_path - looks for files in the current PATH. Returns file path on success, NULL on failure
• link_path - creates a linked list of directories in PATH. Returns pointer to first element of linked list.
• free_linked_path - frees the linked path

BUILTINS search_builtins - searchs for builtins from user input

• _env - prints environment variable
• execute_exit - exits function

HELPER FUNCTIONS

• _getenv - get an environment variable. Returns pointer to the variable
  
• copy_env - copies environment variable. Returns double pointer to copy of environment variable
• free_dblptr - frees a double pointer
• add_node_end - adds a new node at the end of a list_t list. Returns pointer to added node, or NULL
• clear_buff - sets buffer to '\0'
• _putchar - writes character to stdout
• putstring - prints a string
• strfcns - helper string functions:
  _strcat - concatenates two strings. Returns pointer to resulting string
  _strcmp - compares two strings. Returns (-) if s1 < s2, (0) if s1 > s2, 0 if s1 = s2
  _strcpy - copies string from src to dest. Returns pointer to dest
  _strncmp - compares two character strings up to n bytes. Return 0-success, -1-failure
  strlen_rec - finds and returns length of a string
  
• tokenizer - splits a character string into an array of tokens

Jennifer Huang Jennifer's Github Kristen Loyd Kristen's Github

Public Domain, no copyright protection