minishell: writing my own shell

In this project, the goal was to face problems people faced when Windows didn’t exist.

For a big project like that, thank god I don't need to do it alone 🙏
So I joined my friend Teo Rimize to develop it together.

We had to build a command-line interpreter 🤯 A shell that provides a command line user interface with capabilities such as command parsing and execution, signal handling, environment variable management, support for pipes and redirections, and implementation of built-in commands.

An example of a simple command in our minishell.

List of requirements

Have a working history
Handle ’ (single quote) which should prevent the shell from interpreting the meta-characters in the quoted sequence.
Handle " (double quote) which should prevent the shell from interpreting the meta-characters in the quoted sequence except for $ (dollar sign).
Implement redirections:
- < should redirect input.
- > should redirect output.
- << should be given a delimiter, then read the input until a line containing the delimiter is seen. However, it doesn’t have to update the history!
- >> should redirect output in append mode.
Implement pipes (| character). The output of each command in the pipeline is connected to the input of the next command via a pipe.
Handle environment variables ($ followed by a sequence of characters) which should expand to their values.
Handle $? which should expand to the exit status of the most recently executed foreground pipeline.
Handle ctrl-C, ctrl-D and ctrl-\ which should behave like in bash.
- ctrl-C displays a new prompt on a new line.
- ctrl-D exits the shell.
- ctrl-\ does nothing.
Implement the following 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

Bonus features 💡

&& and || with parenthesis for priorities.
Wildcards * work for the current working directory.

Example of a more complex prompt using a redirection to a file and the operator &&.

Grade 🏆

You can also check our code on my GitHub.