minishell

Hive Helsinki (School 42) 9th curriculum project (Rank03)

About · Program Scope · Requirements · Instructions · Testing

About

The repository contains a custom shell, replicating the behavioiur of the bash command line shell. It is the first project in the school 42 curriculum conducted in a team consisting of 2 students. Thus, apart from learning in-depth about the characteristics of the bash language, the logic and setup of a command line shell and how to structure and develop a complex program written in C (consisting of extensive parsing/lexing, command execution of both built-in and external commands and comprehensive signal handling), the setup of a joint git repository and agreement on a suitable and efficient working mode is another pivotal aspect of this project.

Program Scope

The implementation orients closely on a bash shell, the following functionalities are within scope:

PARSING

• assigns tokens to user input based on bash syntax
• sets up and populates process structs containing e.g. command and redirections arrays, file descriptors and heredoc content
• handles single ' and double quotes "
• handles environmental variable expansion via $ character
• handles $? for displaying exit status of most recently executed foreground pipeline

EXECUTION

builtins:

• echo with option -n
• cd with only a relative or absolute path
• pwd with no options
• export with no options
• unset with no options
• env with no options or arguments
• exit with no options

pipes:

• the shell supports chaining builtins and external commands by | operator up to an arbitrary amount of 255 pipes.

redirections:

• handles the following redirections: <, >, <<, >>

signals:

• ctrl + d
• ctrl + c
• ctrl + \

The following functionalities are out of scope:
unclosed quotes, whildcards *, &&, ||, \, ;

Requirements

-gcc compiler with <readline.h>

Instructions

1. Compiling the program

To compile the minishell, clone the repository, cd into the folder and run:

$ make

2. Run the program

Run the executable with the following command:

$ ./minishell

You are now in the minishell environment and can conduct the respective bash commands.

3. Cleaning all binary (.o) and executable files

To delete all files generated with make, run:

$ make fclean

Testing

This library has been tested with [minishell_tester] (https://github.com/LucasKuhn/minishell_tester)