Low Optmized Shell (Losh)

A simple shell for learning purposes.

Building from Source

It is important to say that this project can only be compiled in a linux enviroment, since it uses the linux syscalls direcly, instead of having a preprocessor condition to determine which code has to be compiled.

That been said, make sure to have installed the following dependencies:

• GNU Make
• gcc

You can try changing the compiler in the Makefile to something that you prefer, but it is NOT garanteed that it will work by only doing the this, and maybe you will have to change other things aswell.

Finally, to compile the code you use the following commands:

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

The binary output, by default, is the debug version. You can change the binary to the release version by using the previous commands and adding RELEASE=1 to it:

$ RELEASE=1 make      # or
$ make run RELEASE=1

Developing

File Structure

Within the src directory is where the source code is located. When you compile the code, two more directories will be created on the root directory: bin and obj, both having the binaries executables and the object files, respectively.

In the tests directory are located the tests from the project. Similarly as the proccess described before, when the tests are compiled, two other directories will be created, them been tests/bin and tests/obj and, respectively, storing the binary executable to run the tests and the object files of them.

Lastly, the compile_flags.txt file is destinated to put the include paths of the project, been only a simple mechanism, in this project, to make the LSP recognize those paths, and a simpler version of compile_commands.json and .clangd config file.

Testing

Unfortunately, to run the tests of this project, it is necessary to have installed on the machine the GoogleTest framework, since it is not downloaded on the fly when trying to run the tests for the first time.

Since the GoogleTest framework is written in C++, the test files also happen to be C++ files, but of course calling the source code in C (FFI).

To run the tests, use the command below. Make sure to use the RELEASE=1 flag, otherwise it will NOT compile.

$ RELEASE=1 make test  # or
$ make test RELEASE=1

What have I learned with this?

• C properties
• How to create a makefile in projects with more than just a couple of files
• How to use GDB
• How to create and use clang-format
• How to make syscalls directly from C
• Pipes and communication between processes
• I/O redirection
• Tests in C
• Input parsing