/simple_shell

Creating a simple shell in C

Primary LanguageC

ALX COLLABORATORS PROJECT

simple_shell

Table of Contents

Description

simple_shell is a command line interpreter, or shell, in the tradition of the first Unix shell written by Ken Thompson in 1971. This shell is intentionally minimalistic, yet includes the basic functionality of a traditional Unix-like command line user interface.

Standard functions and system calls employed in simple_shell include:

access, execve, exit, fork, free, fstat, getline, malloc, perror, signal, stat, wait, write.

File Structure

  • AUTHORS - List of contributors to this repository

  • man_1_simple_shell - Manual page for the simple_shell

  • shell.h - program header file

  • [0X02-SHELL_UTILIZATION] - major builtin functions

    • `my exist- checks to see if the user's command matches a builtin

    • _mycd - exits the shell with the option of a specified status

    • `_myhelp - prints the shell's environment variables to the standard output

    • `` - initializes a new environment variable, or modifies an existing one

      • removes an environment variable

  • [helper.c) - helper functions for the builtins

    • int interactive - creates a new environment variable

    • is_delim - finds an environment variable in the environment array

    • int _isalpha` - creates a new environment variable string

    • _atoi - converts a string into a non-negative integer

  • environment.c - functions related to the environment

    • make_env - creates the shell's environment from the parent process

    • free_env - frees the shell's environment

  • errors.c - functions related to printing errors

    • print_error - prints an error message to the standard error

    • _puts2 - prints a string to the standard error

    • _uitoa - converts an unsigned integer to a string

  • memory_allocation.c - memory allocation functions

    • _realloc - a custom realloc function for arrays of pointers

  • new_strtok.c - custom strtok and helper functions

    • check_match - checks if a character matches any in a string

    • new_strtok - a custom strtok for the shell

  • path.c - functions related to executing commands

    • path_execute - executes a command in the PATH

    • find_path - finds the PATH environment variable

    • check_for_path - checks if the command is in the PATH

    • execute_cwd - executes a command with an absolute path

    • check_for_dir - checks if the command contains an absolute path

  • simple_shell.c - essential functions to the shell

    • main - the main function of the program

    • sig_handler - handles SIGINT

  • strfunc.c - functions related to string manipulation

    • _puts - writes a string to standart output

    • _strdup - duplicates a string

    • _strcmpr - compares two strings

    • _strcat - concatenates two strings with a / in the middle

    • _strlen - calculates the length of a string

  • tokenize.c - tokenizing function

    • tokenize - creates an array of tokens from a buffer with a specified delimiter

Features

  • uses the PATH

  • implements builtins

  • handles command line arguments

  • custom strtok function

  • uses exit status

  • shell continues upon Crtl+C (^C)

  • handles comments (#)

  • handles ;

  • custom getline type function

  • handles && and ||

  • aliases

  • variable replacement

  • exit

  • env

  • setenv

  • unsetenv

  • cd

  • help

  • history

Bugs