Windows/Mac/Linux: Google’s ADB and fastboot are incredibly powerful command line tools for customizing your Android phone. Up until now, these tiny tools have been bundled in the gigantic Android SDK, but Google will finally let you download these tools on their own.
The ADB and fastboot tool bundle is a comparatively tiny 3.5MB, versus the 1.6GB it takes to download the Android SDK. We’ve had a guide for a long time that shows the easiest way to get ADB and fastboot, but if you’re just Googling around, you might stumble on sketchy .exe files that could be malicious, or at best are outdated. This official download finally solves that problem, making it much easier (and safer) for regular users to get these tools.
Ever wanted to download adb or fastboot without having to download the whole of Android Studio? | Google+ via Android Police