How do I run an adb shell command?

Switch on developer options and USB debugging on the phone, plug it in, then run adb shell from a machine with platform-tools installed — or run adb shell on its own to get an interactive prompt and type the command without the prefix. If the command produces binary output, such as a screenshot, use adb exec-out instead of adb shell: the plain shell service attaches a terminal, which rewrites newline bytes and corrupts the data.

Do adb shell commands need root?

Not the ones on this reference. They run as the shell user, which can manage packages for its own Android user, read most dumpsys services, write the settings provider, inject input and read shared storage. Root is only needed for things this reference deliberately avoids — reading another app's private data (except through run-as on a debuggable build), writing system partitions, or reading /data/anr directly.

Why does the output look different on my phone?

Either the Android version or the manufacturer. Some flags and fields arrived in a specific release, and those are noted per command. The rest is OEM patching, which hits dumpsys hardest: a dump is debug output whose text is whatever the service author last printed, and manufacturers change it and backport their changes. Read fields by name rather than by position, and treat an unfamiliar shape as a difference rather than as a failure.

Can I run this from a browser instead of a terminal?

For many commands, yes — the Web ADB tools on this site talk to a phone over WebUSB from a Chromium-based desktop browser, with no SDK installed and nothing uploaded. Each page links to the tool that runs its command, when one exists. Two limits are worth knowing: only one program can hold the ADB interface at a time, so a desktop adb server has to be stopped first, and adb forward and adb reverse cannot work in a browser at all.

am force-stop

changes the device

Kills every process and service belonging to one app.

Command: adb shell am force-stop
Commands: Activities and intents (am)
Risk: changes the device

Syntax

am force-stop <package>

Examples

```
am force-stop com.example
```
Stop a misbehaving app without uninstalling or clearing it.
```
top -b -n 1 -m 10
```
Find what is actually burning CPU before you stop anything.

Reading the output

Normally nothing. Treat silence as success and any `Error:`, `Exception` or permission line as failure — and if you want proof, look for the app's processes in `top` afterwards rather than trusting the absence of output.

Output fields

Field	Meaning
(no output)	The command ran.
Error: …	The package could not be resolved, or the call was refused.

What access it needs

No root, no `adb root`, no `su`: an authorised `adb` connection is the whole requirement. `am force-stop` reaches `ActivityManagerService.forceStopPackage`, which checks the caller for `android.Manifest.permission.FORCE_STOP_PACKAGES` and throws otherwise; the Shell package declares exactly that permission in its own manifest (`packages/Shell/AndroidManifest.xml`), which is why the command works from a cable and from almost nowhere else. The same manifest is what makes the default reach wider than most people expect. It also holds `INTERACT_ACROSS_USERS_FULL`, and `runForceStop` starts with its user id set to `UserHandle.USER_ALL`, narrowing only when you pass `--user`. So the plain one-argument form does not stop the app for the person looking at the screen — it stops it in every Android user on the device at once: the work profile, a secondary user, a cloned instance of the same app. If you meant only the user in front of you, name it. Nothing else stands between you and the kill: there is no confirmation, no dry run, no per-package allowance you can revoke, and the platform will not stop you force-stopping a system app. On a user build `adb root` is refused anyway, and it would buy you nothing here, because shell already holds the permission the call demands.

Failure messages, decoded

Message	Meaning
Error: Unknown option: --user0	`runForceStop` accepts exactly one option, `--user`. Anything else is echoed on stderr and the method returns -1 before calling `forceStopPackage`, so a joined `--user0`, a `-u` abbreviation or a stray `--all` leaves the app running while the command reads like a warning rather than a refusal. Check the exit status, not the tone of the line.
Exception occurred while executing 'force-stop':	A `Throwable` escaped `onCommand`; stderr carries a blank line, this banner and the trace. `java.lang.IllegalArgumentException: Argument expected after "force-stop"` means no package name was given. A `java.lang.SecurityException` naming `android.permission.FORCE_STOP_PACKAGES` means the call did not come from shell or root, which over a cable normally means you are inside `run-as` and no longer uid 2000.
Unknown command: force stop	The hyphen is part of the subcommand name. Quoted or split, `am` sees `force` and `handleDefaultCommands` prints this on stdout, returning -1 without touching any process. It looks nothing like the silence a successful force-stop produces, which is the one good thing about it.
cmd: Can't find service: activity	`am` is a wrapper around `cmd activity`, and `cmd` could not find that service in the service manager. Nothing was stopped. Expected during boot, before `system_server` publishes `activity`; it is not a sign that the package name was wrong.

What it changes, and the way back

Nothing is deleted and the app starts again the next time it is launched or a broadcast wakes it — but unsaved state in its process is gone, and the alarms and jobs it had scheduled are cancelled until it runs again. There is no undo command; the cure is to open the app.

Version and vendor notes

Force-stopping from a process table sorted by CPU is an easy mis-click, and the app you meant to leave alone is the one that loses its unsaved state.
This is not the same as disabling: the app is free to start again at any moment.

We have a UI for this

Android System Monitor runs this command over USB and parses what comes back — a Chromium browser, no SDK, nothing uploaded.

Open Android System Monitor

Related commands

Commands that turn up in the same session as am force-stop.

Command	What it does
top	A one-shot process table: CPU share, memory, state and command line.
dumpsys meminfo	Which processes are using the most memory, measured as proportional set size.
am start	Starts an activity by component or by intent — the fastest way to test whether a deep link resolves.

More Activities and intents (am) commands

Command	What it does
am broadcast	Sends a broadcast intent, which is how SystemUI demo mode and other platform receivers are driven from a shell.

Checked against AOSP, toybox and kernel sources while writing the parsers behind our Web ADB tools. Where a behaviour genuinely varies by Android version or manufacturer, this page says so instead of giving a number that would be wrong on half the phones out there.