Android Operating System

This page is about the Android operating system. For Android programming, see Android Programming.

For hardware that can run Android, see Hardware > Mobile Phones. Note that some single-board computers like Raspberry Pi can also run Android and a version called Android Things.

There are multiple versions of Android available, including:

Your phone's factory Android system
LineageOS - Formerly Cyanogen, LineageOS is a more freedom and security focused Android distribution without Google apps. For a reference, see the Nexus 5X Phone page.
Maru OS - an Android distribution that touts an X11 desktop system when you attach an HDMI monitor

Instead of using Google Play Store to download apps, you can use F-Droid as a package manager.

Here are a few apps I'd recommend:

Topics

Put an Android phone into usb debug mode by going to Settings | System | About and tapping Build Number 7 times.
How to use adb to install and run APK packages
How to use adb and fastboot to flash a custom recovery rom (e.g. TeamWin TWRP)
How to transfer files (adb, ftp, sftp, bluetooth)
How to use termux to script Python, Node, Ruby, etc
How to run Python on Android (and script/make home buttons for actions)
How to download and install APKs (Download packages and source from F-Droid)
For programming topics like how to build apps or get apps into the play store, see Android Programming.
For how to install Android operating systems and supported hardware, see Mobile Devices