01 — Parsing
Reading between commands.
Before executing anything, the shell needs to understand what the user wrote. Quotes, spaces, variables, redirections and pipes quickly turn a simple line of text into a real parsing problem.
Fig. 01
Unix / System programming / 2024
42 project
Minishell
Building a minimalist shell to understand parsing, processes, redirections and pipes.
Stack
- C
- Unix
- Syscall
Skills gained
- Building a parser to interpret command lines
- Managing processes with fork, execve and wait
- Understanding pipes, redirections and environment variables
- Structuring a longer and more complex C project
Links
Minishell consists in building a shell inspired by bash, able to interpret commands, handle pipes, redirections, environment variables and processes. It is a dense project that combines parsing, Unix system programming and the organization of a larger C codebase.
02 — Processes
Making Unix talk.
The core of the project relies on creating and coordinating processes. Fork, execve, wait, pipes and redirections help reveal how a shell actually orchestrates commands behind an apparently simple interface.
Fig. 02
03 — Robustness
Handling weird cases.
Minishell is mostly an exercise in robustness. It requires handling errors, signals, unexpected behaviors and many edge cases without losing control of the program’s internal state.
Fig. 03