Low Optmized Shell (Losh)

A simple shell for learning purposes.

Building from Source

This project can only be compiled on a Linux environment, as it uses Linux syscalls directly without preprocessor conditions to determine platform-specific code.

Ensure you have the following dependencies installed:

• GNU Make
• gcc

To compile the code, use the following commands:

$ make      # to build
$ make run  # to build and run

To remove generated files, use:

$ make clean      # to remove the `.o`, `.d`, and binary files
$ make clean_all  # to remove these files from both the main application and the tests

Developing

File Structure

• src/: Contains the source code.
• obj/: Created during compilation, contains compiled objects and dependencies.
• tests/: Contains the project's test files, with a similar structure to the main source code.
• compile_flags.txt: Specifies include paths for the project to help the LSP in recognizing those paths, acting as a simpler version of compile_commands.json and the .clangd config file.

Testing

This project uses the GoogleTest framework for testing. Note that GoogleTest is not downloaded automatically when running tests for the first time, which is not the recommended usage for it, but this project is just for learning.

Since GoogleTest is written in C++, the test files are also C++ files but call the C code using FFI.

To run the tests, use:

make tests

What have I learned from this?

• C properties
• Creating Makefiles for projects with multiple files
• Using GDB
• Creating and using clang-format
• Making syscalls directly from C
• Pipes and communication between processes
• IO redirection
• Writing tests in C
• Input parsing
• Basic FFI use