GitHub - EnessAli/bash-interpreter

A POSIX-compliant Unix shell built from scratch in C, supporting command execution, pipes, redirections, heredoc, environment variables, and signal handling — closely mirroring Bash behavior.

Features

Execution

Command resolution via PATH traversal
Absolute and relative path execution
Exit status propagation ($?)

Built-in Commands

Command	Description
`echo`	Print with `-n` flag support
`cd`	Change directory with `~` and `-`
`pwd`	Print working directory
`export`	Set/display environment variables
`unset`	Remove environment variable
`env`	Display environment
`exit`	Exit with status code

Redirections & Pipes

> output redirect, >> append
< input redirect
<< heredoc with delimiter
| pipeline with proper process chaining

Quoting & Expansion

Single quotes: literal string
Double quotes: variable expansion inside
$VAR and ${VAR} expansion
$? last exit status

Signal Handling

Ctrl+C → new prompt (SIGINT)
Ctrl+D → clean exit (EOF)
Ctrl+\ → ignored (SIGQUIT)

Build & Run

make
./minishell

minishell$ echo "Hello, $USER!"
Hello, yourname!
minishell$ ls -la | grep .c | wc -l
42

Architecture

lexer → tokenizer → parser (AST) → expander → executor
                                                ├── builtin handler
                                                ├── pipe manager
                                                └── redirect handler

Tech Stack

C Readline POSIX Fork/Exec Pipe Signal Handling AST