# SerenityOS build instructions

## Prerequisites

Make sure you have all the dependencies installed:

### Debian / Ubuntu

```console
sudo apt install build-essential cmake curl libmpfr-dev libmpc-dev libgmp-dev e2fsprogs ninja-build qemu-system-i386 qemu-utils ccache rsync
```

#### GCC 10

On Ubuntu gcc-10 is available in the repositories of 20.04 (Focal) and later - add the `ubuntu-toolchain-r/test` PPA if you're running an older version:

```console
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
```

On Debian you can use the Debian testing branch:

```console
sudo echo "deb http://http.us.debian.org/debian/ testing non-free contrib main" >> /etc/apt/sources.list
sudo apt update
```

Now on Ubuntu or Debian you can install gcc-10 with apt like this:

```console
sudo apt install gcc-10 g++-10
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-10 900 --slave /usr/bin/g++ g++ /usr/bin/g++-10
```

If you don't want to stay on the Debian testing branch you can switch back by running:

```console
sudo sed -i '$d' /etc/apt/sources.list
sudo apt update
```

#### QEMU 5 or later

QEMU version 5 is available in Ubuntu 20.10. For earlier versions, you can build version 6 using the `Toolchain/BuildQemu.sh` script.
You may need the gtk+ 3.0 dev package:

```console
sudo apt install libpixman-1-dev libgtk-3-dev
```

### Fedora

```console
sudo dnf install binutils-devel curl cmake mpfr-devel libmpc-devel gmp-devel e2fsprogs ninja-build patch ccache rsync @"C Development Tools and Libraries" @Virtualization
```

### Other systems

There is also documentation for installing the build prerequisites for some less commonly used systems:

* [Other Linux distributions and *NIX systems](BuildInstructionsOther.md)
* [Windows](BuildInstructionsWindows.md)
* [macOS](BuildInstructionsMacOS.md)

## Build

In order to build SerenityOS you will first need to build the toolchain by running the following command:

```console
$ Meta/serenity.sh rebuild-toolchain
```

Later on, when you use `git pull` to get the latest changes, there's (usually) no need to rebuild the toolchain.

Run the following command to build and run SerenityOS:

```console
$ Meta/serenity.sh run
```

This will compile all of SerenityOS and install the built files into the `Build/i686/Root` directory inside your Git
repository. It will also build a disk image and start SerenityOS using QEMU.

Note that the `anon` user is able to become `root` without a password by default, as a development convenience.
To prevent this, remove `anon` from the `wheel` group and he will no longer be able to run `/bin/su`.

If you want to test whether your code changes compile without running the VM you can use
`Meta/serenity.sh build`. The `serenity.sh` script also provides a number of other commands. Run the script without
arguments for a list.

## Ports

To add a package from the ports collection to Serenity, for example curl, change into the `Ports/curl` directory and
run `./package.sh`. The source code for the package will be downloaded and the package will be built. The next time you
start Serenity, `curl` will be available.

## More information

At this point you should have a fully functioning VM for SerenityOS. The [advanced build instructions guide](AdvancedBuildInstructions.md)
has more information for some less commonly used features of the build system.