Name of the Project

Simple Shell Project

Description

This project is a simple shell implementation, also known as a command-line interpreter. It provides a basic command-line interface where users can interact with the operating system by executing various commands and programs.

Features

• Command execution: The shell allows users to execute commands and run programs by typing them into the command prompt.
• Input/output redirection: Users can redirect input and output streams, enabling them to read input from files or write output to files.
• Pipeline support: Users can create command pipelines by connecting multiple commands together, allowing the output of one command to serve as input to another.
• Built-in commands: The shell provides a set of built-in commands that can be executed directly, such as cd for changing directories or exit for terminating the shell.
• Error handling: The shell handles errors gracefully, providing appropriate error messages and returning exit codes.

Technologies Used

• C programming language: The shell is implemented using the C programming language, taking advantage of its low-level system access and standard libraries.
• Operating system interfaces: The shell utilizes operating system interfaces, such as system calls, to interact with the underlying operating system and execute commands.

Files

Name	Description
shell.h	Header file program.
main.c	Main function, interactive and non-interactive.
new_procees.c	Function that creates a new process.
own_cd.c	Change the working directory.
own_env.c	Function that prints environment variables.
own_exit.c	Exit shell with a given state.
own_help.c	Function that prints help (get information about a command)
read_line.c	Read a line from stdin.
read_stream.c	Read a line from the stream.
shell_interactive.c	Run shell interactive mode.
shell_no_interactive.c	Run shell non-interactive mode.
split_line.c	Split a string into tokens.
execute_args.c	Number of builtin functions.

List of functions and system calls.

• chdir (man 2 chdir)
• exit (man 3 exit)
• fork (man 2 fork)
• free (man 3 free)
• getline (man 3 getline)
• isatty (man 3 isatty)
• malloc (man 3 malloc)
• perror (man 3 perror)
• strtok (man 3 strtok)
• waitpid (man 2 waitpid)

Install

Clone this repo and compile as follow:

gcc -Wall -Werror -Wextra -pedantic -std=gnu89 *.c -o hsh

Usage

Interactive mode: ./hsh

Non-interactive mode: echo "/bin/ls" | ./hsh

Built-ins

• cd
• env
• help
• exit
• setenv
• unsetenv

Examples

• Run shell in interactive mode:

 $ ./hsh
 simple_prompt$ ls -l
 total 72
-rw-r--r-- 1 root root   771 Nov 16 12:01 execute_args.c
-rwxr-xr-x 1 root root 20192 Nov 16 12:31 hsh
-rw-r--r-- 1 root root   307 Nov 16 08:39 main.c
-rw-r--r-- 1 root root   646 Nov 16 11:59 new_process.c
-rw-r--r-- 1 root root   384 Nov 16 12:28 own_cd.c
-rw-r--r-- 1 root root   338 Nov 16 12:28 own_env.c
-rw-r--r-- 1 root root   284 Nov 16 12:29 own_exit.c
-rw-r--r-- 1 root root   591 Nov 16 12:31 own_help.c
-rw-r--r-- 1 root root   590 Nov 16 09:13 read_line.c
-rw-r--r-- 1 root root   815 Nov 16 12:26 read_stream.c
-rw-r--r-- 1 root root   677 Nov 16 12:27 shell.h
-rw-r--r-- 1 root root   516 Nov 16 08:38 shell_interactive.c
-rw-r--r-- 1 root root   442 Nov 16 12:07 shell_no_interactive.c
-rw-r--r-- 1 root root   848 Nov 16 09:35 split_line.c

 $ /hsh
 simple_prompt$ echo “Hello, World!”
 “Hello, World!”

• Run shell in non-interactive mode:

 $ echo "/bin/ls" | ./hsh
 execute_args.c  new_process.c  own_exit.c   read_stream.c        shell_no_interactive.c
hsh             own_cd.c       own_help.c   shell.h              split_line.c
main.c          own_env.c      read_line.c  shell_interactive.c

 

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