A minimal Unix-like shell implemented in C, built to understand how command execution, process management, and system calls work at the operating system level. This project focuses on low-level interaction with Linux rather than feature completeness.
This shell provides a basic REPL (Read–Eval–Print Loop) that reads user input, parses commands, resolves executable paths, and executes programs using Linux system calls. It implements core shell functionality from first principles to explore how user-space programs interact with the operating system.
The goal of this project is learning systems programming concepts, not replicating a full-featured shell like bash or zsh.
- Interactive command prompt (REPL)
- Command parsing and argument handling
- Execution of external programs
- Built-in commands:
exit– terminate the shellecho– print arguments to stdouttype– identify built-in vs external commands
- PATH resolution and executable lookup
- Invalid command handling
- Signal handling (basic support)
- Direct use of Linux system calls (
fork,exec,wait, file descriptors)
This project provides hands-on experience with:
- Process creation and execution (
fork,exec) - Parent–child process relationships
- Command dispatch and program loading
- File descriptors and standard I/O
- Environment variables and PATH resolution
- Basic signal handling
- REPL design pattern
- User–kernel interaction through syscalls
High-level flow:
- Print shell prompt
- Read user input
- Parse input into command + arguments
- Handle built-in commands
- Resolve executable path
- Create child process (
fork) - Execute program (
exec) - Wait for completion (
wait) - Loop back to prompt
gcc -o minishell main.cThis project prioritizes:
- understanding OS-level behavior
- correctness of system call usage
- clarity of control flow
- learning Linux internals
This is not a full POSIX-compliant shell. The following features are intentionally not implemented yet:
- pipelines
- redirection
- job control
- command history
- autocompletion
- advanced quoting
- background processes
- scripting
These are planned extensions for future versions.
The purpose of this project is to learn how real shells work internally by building one from scratch in C. It is part of a broader effort to understand operating systems, low-level programming, and Linux internals through practical implementation.
Planned improvements include:
- I/O redirection (
>,<,>>) - pipelines (
|) - command history
- signal handling improvements
- job control
- improved parsing and tokenization
- structured command execution pipeline