adb

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# adb

Connect to and control Android devices via the Android Debug Bridge (`adb`).

## Orientation

```bash
which -a adb
adb version
adb devices
adb devices -l    # long output with device details
```

## Key concepts

- **Device state**: `device` (ready), `offline` (unreachable), `unauthorized`
  (connected but not approved — a popup appears on the device asking to allow
  debugging; the user must accept)
- **Serial**: USB devices use a serial number; emulators use `emulator-NNNN`;
  wireless connections use `IP:PORT`
- **Multiple devices**: when more than one device is connected, ALL `adb`
  commands require `-s <serial>` to specify the target. Without it, commands
  fail with `error: more than one device/emulator`.
- **$ANDROID_SERIAL**: set this env var to target a device without `-s`.

## Device authorization

On first connection, the device shows an "Allow USB debugging?" popup with the
host's RSA key fingerprint. The user must tap "Allow" (or "OK"). Until then,
the device shows as `unauthorized` and all `adb shell` commands fail.

```
adb devices
# emulator-5554    unauthorized  ← user needs to accept popup on device
# ...after accepting...
# emulator-5554    device
```

To re-trigger the authorization popup:
```bash
adb kill-server
adb start-server
adb devices
```

"Always allow from this computer" checkbox prevents future prompts for that
key. To revoke all authorizations on the device:
```bash
adb -s <serial> shell settings put global adb_enabled 0
adb -s <serial> shell settings put global adb_enabled 1
# Or via Developer Options → "Revoke USB debugging authorizations"
```

## Checking and enabling USB debugging

### Read state
```bash
adb -s <serial> shell settings get global adb_enabled
# 1 = enabled, 0 = disabled
```

### Enable/disable via settings provider
```bash
adb -s <serial> shell settings put global adb_enabled 1   # enable
adb -s <serial> shell settings put global adb_enabled 0   # disable
```

Note: changing the setting via `settings put` may not flip the UI toggle in
Developer Options, but it affects the ADB daemon behavior. The UI toggle is
the canonical way to enable/disable; the settings command is a programmatic
alternative.

## Wireless debugging (Android 11+)

### Check state
```bash
adb -s <serial> shell settings get global adb_wifi_enabled
# 1 = enabled, 0 = disabled

adb -s <serial> shell settings get global adb_wifi_port
# port number, or null if not active
```

### Enable via settings provider
```bash
adb -s <serial> shell settings put global adb_wifi_enabled 1
```

This sets the flag but does NOT start the wireless ADB daemon or assign a
port on all devices. To reliably start wireless ADB:

### Classic method (`adb tcpip`) — works on all Android versions
```bash
# 1. Device must be connected via USB first
# 2. Switch ADB to TCP/IP mode on a specific port
adb -s <serial> tcpip 5555
# "restarting in TCP mode port: 5555"

# 3. Get the device's IP address
adb -s <serial> shell ip addr show wlan0 | grep "inet "
# Or for emulators:
adb -s <serial> shell ip addr show eth0 | grep "inet "

# 4. Connect wirelessly
adb connect <device_ip>:5555

# 5. Verify — now shows both USB and wireless connections
adb devices
```

### Wireless debugging pairing (Android 11+) — no USB cable needed
On the device, open Developer Options → Wireless debugging → "Pair device with
pairing code". Keep that dialog open while pairing. It shows a temporary
pairing code, IP, and a **pairing port** (different from the connection port).
Treat the code like a short-lived credential: do not put it in notes, scripts,
or shared logs. Enter it at the interactive prompt rather than putting it in
command arguments.

```bash

From jason-riddle/agent-skills, MIT.

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