Minishell

The line is split into words and operators (lexer), then grouped into commands with their redirections (parser). Single and double quotes must be respected, variables such as $HOME or $? expanded, and the <, >, >> redirections and the << heredoc handled.

For a chain of piped commands, the shell creates the pipe()s, calls fork() once per command, wires inputs and outputs with dup2(), then starts the program with execve() after looking it up in PATH. Builtins (cd, echo, export, unset, env, pwd, exit) are written by hand, since some of them must change the shell itself.

Signals behave differently depending on the context: Ctrl+C clears the line at the prompt, interrupts a running command, and cancels a heredoc. All memory is freed on every cycle, and the environment is our own list, which works even when started with no environment at all.

Four colour themes for the prompt, picked at launch with -t. It was also my first real two-person project: splitting parsing and execution required a clear definition of what goes from one to the other.