Chapter 1: Getting Started

Chapter 2: Using Atom

Chapter 3: Hacking Atom

Chapter 4: Behind Atom

Reference: API

Appendix A: Resources

Appendix B: FAQ

Appendix C: Shadow DOM

Appendix D: Upgrading to 1.0 APIs

Appendix E: Atom server-side APIs

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Hacking on Atom Core

If you're hitting a bug in Atom or just want to experiment with adding a feature to the core of the system, you'll want to run Atom in Dev Mode with access to a local copy of the Atom source.

Fork the atom/atom repository

Follow the GitHub Help instructions on how to fork a repo.

Cloning and bootstrapping

Once you've set up your fork of the atom/atom repository, you can clone it to your local machine:

git clone git@github.com:your-username/atom.git

From there, you can navigate into the directory where you've cloned the Atom source code and run the bootstrap script to install all the required dependencies:

cd where-you-cloned-atom
script/bootstrap

cd where-you-cloned-atom
script/bootstrap

cd where-you-cloned-atom
script\bootstrap

Running in Development Mode

Once you have a local copy of Atom cloned and bootstrapped, you can then run Atom in Development Mode. But first, if you cloned Atom to somewhere other than ~/github/atom%USERPROFILE%\github\atom you will need to set the ATOM_DEV_RESOURCE_PATH environment variable to point to the folder in which you cloned Atom. To run Atom in Dev Mode, use the --dev parameter from the terminal:

atom --dev path-to-open

Note: If the atom command does not respond in the terminal, then try atom-dev or atom-beta. The suffix depends upon the particular source code that was cloned.

There are a couple benefits of running Atom in Dev Mode:

  1. When the ATOM_DEV_RESOURCE_PATH environment variable is set correctly, Atom is run using the source code from your local atom/atom repository. This means that you don't have to run script/buildscript\build every time you change code. Just restart Atom 👍
  2. Packages that exist in ~/.atom/dev/packages%USERPROFILE%\.atom\dev\packages are loaded instead of packages of the same name normally loaded from other locations. This means that you can have development versions of packages you use loaded but easily go back to the stable versions by launching without Dev Mode.
  3. Packages that contain stylesheets, such as syntax themes, will have those stylesheets automatically reloaded by the dev-live-reload package. This does not live reload JavaScript or CoffeeScript files — you'll need to reload the window (window:reload) to see changes to those.

Running Atom Core Tests Locally

In order to run Atom Core tests from the terminal, first be certain to set the ATOM_DEV_RESOURCE_PATH environment variable as mentioned above and then:

cd path-to-your-local-atom-repo
atom --test spec

Building

In order to build Atom from source, you need to have a number of other requirements and take additional steps.

Requirements
  • macOS 10.9 or later
  • Node.js 10.12 or later (we recommend installing it via nvm)
  • npm 6.12 or later (run npm install -g npm)
  • Python v2.6.x, v2.7.x or v3.5+
  • Command Line Tools for Xcode (run xcode-select --install to install)
  • Node.js 10.12 or later (the architecture of node available to the build system will determine whether you build 32-bit or 64-bit Atom)
  • npm 6.12 or later (run npm install -g npm)
  • Python v2.6.x, v2.7.x, or v3.5+
    • Get Python from the Microsoft Store, or
    • Download Python from https://www.python.org/downloads/.
      • For Python 2, be sure to install in the default location, or check "Add Python 2.x to PATH" before installing.
      • For Python 3, check "Add Python 3.x to PATH", or change the install path to [Your_Drive_Letter]:\Python37 e.g. C:\Python37, (even if your version of Python 3 isn't 3.7, that's one place where the scripts will look.)
      • If python isn't found by the bootstrap script, create a symbolic link to the directory containing python.exe using e.g.: mklink /d %SystemDrive%\Python27 D:\elsewhere\Python27(Links should be set at either %SystemDrive%\Python27 or %SystemDrive%\Python37, regardless of what version of Python you actually have.)

  • C++ build tools:

    Also ensure that:

    • The default installation folder is chosen so the build tools can find it
    • If using Visual Studio make sure Visual C++ support is selected/installed
    • If using Visual C++ Build Tools make sure a Windows SDK (Windows 8 SDK or Windows 10 SDK) is selected/installed
    • A git command is in your path
    • Set the GYP_MSVS_VERSION environment variable to the Visual Studio/Build Tools version (2015 or 2017.) e.g. [Environment]::SetEnvironmentVariable("GYP_MSVS_VERSION", "2015", "User") in PowerShell (or set it in Windows advanced system settings).

Ubuntu LTS 16.04 64-bit is the recommended platform.

Requirements
  • OS with 64-bit or 32-bit architecture
  • C++11 toolchain
  • Git
  • Node.js 10.12 or later (we recommend installing it via nvm)
  • npm 6.12 or later (run npm install -g npm)
  • Python 2.6.x, 2.7.x or 3.5+
  • Development headers for libsecret.

For more details, scroll down to find how to setup a specific Linux distro.

Ubuntu / Debian

  • Install GNOME headers and other basic prerequisites:

    sudo apt-get install build-essential git libsecret-1-dev fakeroot rpm libx11-dev libxkbfile-dev

  • If script/build exits with an error, you may need to install a newer C++ compiler with C++11:

    sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-5 g++-5
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-5 80 --slave /usr/bin/g++ g++ /usr/bin/g++-5
sudo update-alternatives --config gcc # choose gcc-5 from the list
Fedora 22+
sudo dnf --assumeyes install make gcc gcc-c++ glibc-devel git-core libsecret-devel rpmdevtools libX11-devel libxkbfile-devel
Fedora 21 / CentOS / RHEL
sudo yum install -y make gcc gcc-c++ glibc-devel git-core libsecret-devel rpmdevtools
Arch
sudo pacman -S --needed gconf base-devel git nodejs npm libsecret python libx11 libxkbfile
Slackware
sbopkg -k -i node -i atom
openSUSE
sudo zypper install nodejs nodejs-devel make gcc gcc-c++ glibc-devel git-core libsecret-devel rpmdevtools libX11-devel libxkbfile-devel
Instructions
script/build

To also install the newly built application, use script/build --install.

script\build

To also install the newly built application, use script\build --create-windows-installer and launch one of the generated installers.

script/build

To also install the newly built application, use the --create-debian-package or --create-rpm-package option and then install the generated package via the system package manager.

script/build Options
  • --code-sign: signs the application with the GitHub certificate specified in $ATOM_MAC_CODE_SIGNING_CERT_DOWNLOAD_URL.
  • --compress-artifacts: zips the generated application as out/atom-mac.zip.
  • --install[=dir]: installs the application at ${dir}/Atom.app for dev and stable versions or at ${dir}/Atom-Beta.app for beta versions; ${dir} defaults to /Applications.
script\build Options
  • --code-sign: signs the application with the GitHub certificate specified in $WIN_P12KEY_URL.
  • --compress-artifacts: zips the generated application as out\atom-windows.zip.
  • --create-windows-installer: creates an .exe and two .nupkg packages in the out directory.
  • --install[=dir]: installs the application in ${dir}\Atom\app-dev; ${dir} defaults to %LOCALAPPDATA%.
script/build Options
  • --compress-artifacts: zips the generated application as out/atom-{arch}.tar.gz.
  • --create-debian-package: creates a .deb package as out/atom-{arch}.deb
  • --create-rpm-package: creates a .rpm package as out/atom-{arch}.rpm
  • --install[=dir]: installs the application in ${dir}; ${dir} defaults to /usr/local.
Troubleshooting

Use this search to get a list of reports about build errors on macOS.

Common Errors

  • node is not recognized

    • If you just installed Node.js, you'll need to restart Command Prompt before the node command is available on your path.

  • msbuild.exe failed with exit code: 1

    • If using Visual Studio, ensure you have the Visual C++ component installed. Go into Add/Remove Programs, select Visual Studio, press Modify, and then check the Visual C++ box.
    • If using Visual C++ Build Tools, ensure you have the Windows 8 SDK or Windows 10 SDK component installed. Go into Add/Remove Programs, select Visual C++ Build Tools, press Modify and then check the "Windows 8 SDK" or "Windows 10 SDK" box.

  • script\build stops with no error or warning shortly after displaying the versions of node, npm and Python

    • Make sure that the path where you have checked out Atom does not include a space. For example, use C:\atom instead of C:\my stuff\atom.
    • Try moving the repository to C:\atom. Most likely, the path is too long. See issue #2200.

  • error MSB4025: The project file could not be loaded. Invalid character in the given encoding.

  • 'node_modules\.bin\npm' is not recognized as an internal or external command, operable program or batch file.

    • This occurs if the previous build left things in a bad state. Run script\clean and then script\build again.

  • script\build stops at installing runas with Failed at the runas@x.y.z install script.

    • See the next item.

  • error MSB8020: The build tools for Visual Studio 201? (Platform Toolset = 'v1?0') cannot be found.

    • Try setting the GYP_MSVS_VERSION environment variable to 2015 or 2017 depending on what version of Visual Studio/Build Tools is installed and then script\clean followed by script\build (re-open the Command Prompt if you set the variable using the GUI).

  • 'node-gyp' is not recognized as an internal or external command, operable program or batch file.

    • Try running npm install -g node-gyp, and run script\build again.

  • Other node-gyp errors on first build attempt, even though the right Node.js and Python versions are installed.

    • Do try the build command one more time as experience shows it often works on second try in many cases.
Windows build error reports
  • If all else fails, use this search to get a list of reports about build errors on Windows, and see if yours has already been reported.
  • If it hasn't, please open a new issue with your Windows version, architecture (x86 or x64), and a text dump of your build output, including the Node.js and Python versions.
TypeError: Unable to watch path

If you get following error with a big traceback right after Atom starts:

TypeError: Unable to watch path

you have to increase number of watched files by inotify. For testing if this is the reason for this error you can execute:

sudo sysctl fs.inotify.max_user_watches=32768

then restart Atom. If Atom now works fine, you can make this setting permanent:

echo 32768 | sudo tee -a /proc/sys/fs/inotify/max_user_watches

See also #2082.

/usr/bin/env: node: No such file or directory

If you get this notice when attempting to run any script, you either do not have
Node.js installed, or node isn't identified as Node.js on your machine. If it's
the latter, this might be caused by installing Node.js via the distro package
manager and not nvm, so entering sudo ln -s /usr/bin/nodejs /usr/bin/node into
your terminal may fix the issue. On some variants (mostly Debian based distros)
you can use update-alternatives too:

sudo update-alternatives --install /usr/bin/node node /usr/bin/nodejs 1 --slave /usr/bin/js js /usr/bin/nodejs
AttributeError: 'module' object has no attribute 'script_main'

If you get following error with a big traceback while building Atom:

sys.exit(gyp.script_main()) AttributeError: 'module' object has no attribute 'script_main' gyp ERR!

you need to uninstall the system version of gyp.

On Fedora you would do the following:

sudo yum remove gyp
Linux build error reports

Use this search
to get a list of reports about build errors on Linux.