Connecting to Devices — Listing, Selecting, and Waiting on Transports

adb devices is the most-typed adb command. The follow-on traps are real: scripts run before the device is actually online, multi-device shells fail with more than one device/emulator, Linux misses udev rules, and tutorials reference a fictional wait-for-device-online form. This skill encodes the truth set.

When to use this skill

• The user runs adb shell with two devices plugged in and gets error: more than one device/emulator.
• The user reports a device showing as unauthorized, offline, or no permissions in adb devices.
• The user wants a CI script to wait until a device finishes booting before running tests.
• The user copy-pasted adb wait-for-device-online from a blog post and it errors with usage text.
• The user is on Linux and a freshly plugged phone never appears in adb devices.

When NOT to use this skill

• The user wants the high-level architecture / server lifecycle / env vars — use ../../architecture/understanding-adb-architecture/SKILL.md.
• The user wants Wi-Fi / wireless debugging — use ../connecting-over-wifi/SKILL.md.
• The user wants to install or clear app state on the connected device — use ../../apps/installing-and-managing-apps/SKILL.md.

Prerequisites