# Ruby Hacking Guide¶ ↑

This document gives some helpful instructions which should make your experience as a Ruby core developer easier.

## Setup¶ ↑

### Make¶ ↑

It’s common to want to compile things as quickly as possible. Ensuring `make` has the right `--jobs` flag will ensure all processors are utilized when building software projects. To do this effectively, you can set `MAKEFLAGS` in your shell configuration/profile:

    # On macOS with Fish shell:
    export MAKEFLAGS="--jobs "(sysctl -n hw.ncpu)

    # On macOS with Bash/ZSH shell:
    export MAKEFLAGS="--jobs $(sysctl -n hw.ncpu)"

    # On Linux with Fish shell:
    export MAKEFLAGS="--jobs "(nproc)

    # On Linux with Bash/ZSH shell:
    export MAKEFLAGS="--jobs $(nproc)"

## Configure Ruby¶ ↑

It’s generally advisable to use a build directory.

    ./autogen.sh
    mkdir build
    cd build
    ../configure --prefix $HOME/.rubies/ruby-head
    make install

### Without Documentation¶ ↑

If you are frequently building Ruby, this will reduce the time it takes to `make install`.

    ../configure --disable-install-doc

## Running Ruby¶ ↑

### Run Local Test Script¶ ↑

You can create a file in the Ruby source root called `test.rb`. You can build `miniruby` and execute this script:

    make run

If you want more of the standard library, you can use `runruby` instead of `run`.

### Run Bootstrap Tests¶ ↑

There are a set of tests in `bootstraptest/` which cover most basic features of the core Ruby language.

    make test

### Run Extensive Tests¶ ↑

There are extensive tests in `test/` which cover a wide range of features of the Ruby core language.

    make test-all

You can run specific tests by specifying their path:

    make test-all TESTS=../test/fiber/test_io.rb

### Run RubySpec Tests¶ ↑

RubySpec is a project to write a complete, executable specification for the Ruby programming language.

    make test-all test-rubyspec