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.

dumpsys activity activities

read-only

Which app is in the foreground, and the task and stack structure behind it.

Command: adb shell dumpsys activity activities
Commands: System services (dumpsys)
Risk: read-only

Syntax

dumpsys activity activities

Examples

```
dumpsys activity activities | grep -E 'topResumedActivity|mResumedActivity' | head -n 12
```
Get just the foreground component. Filtering on the phone is what keeps the transfer small.
```
dumpsys activity activities
```
The whole thing — a hundred kilobytes on a phone that has been awake a while.

Reading the output

The full dump prints every task in every stack on every display, so filter it. Four different lines answer "what is in front", and they do not always agree: prefer `topResumedActivity`, which is exactly the question, and treat `mCurrentFocus` as the last resort — it names the focused *window*, which may be the keyboard or a system dialog while the app behind it is still the app the user is running.

Output fields

Field	Meaning
topResumedActivity=	The one activity with top-resumed state. Android 10 and later.
mResumedActivity: / ResumedActivity:	A stack's resumed activity. Several can print; the first is normally the answer.
mFocusedApp=	The focused app token. Correct in practice, one indirection from the question.
mCurrentFocus=	The focused window — possibly the IME or a dialog rather than an app.
u0 com.example/.MainActivity	The Android user id, then the component. Often written relative to the package.

What access it needs

`ActivityManagerService.doDump` opens with `DumpUtils.checkDumpAndUsageStatsPermission` under the tag `ActivityManager`, so `android.permission.DUMP` plus `android.permission.PACKAGE_USAGE_STATS`, both declared by the Shell package, with `SHELL_UID` short-circuiting the app-op check. That is the entire requirement: no root, no `adb root`, no accessibility service, and no "Usage access" grant in Settings — which is why a foreground-app readout is one of the few genuinely privileged-looking things a cable can do without unlocking anything. What shell does not get is a way to make it cheap. Piping through `grep` filters after `system_server` has already built the whole dump, so the work on the phone is identical either way and what you save is only the transfer. There is one more thing the argument parser will do that no permission protects you from: when the word after `activity` is not a recognised section, the dump first tries to match it against a running activity and then, failing that, **hands the whole argument list to the activity manager's shell command interpreter and runs it**. `dumpsys activity <something>` is therefore not guaranteed to be a read. Keep the word `activities` exactly as spelled, or use the Android System Monitor, which sends the filtered read form and nothing else.

Failure messages, decoded

Message	Meaning
Bad activity command, or no activities match: activites	Printed on stdout, followed by `Use -h for help.`, after three things have already been tried: the word was not a known section, it did not match any running activity, and it was then executed as an activity-manager shell command which returned a failure. A typo is harmless here only because the shell command also failed — a typo that happens to spell a real subcommand is not a typo, it is a command.
Unknown argument: --activities; use -h for help	Options are the dash-prefixed ones; `activities` is a command, not an option, so writing it with dashes lands in the option loop. Unlike the package manager's version of this line, the activity dump prints it and returns immediately, so you get this line and nothing else rather than a default dump — which at least makes the mistake obvious.
Permission Denial: can't dump ActivityManager from from pid=4821, uid=10231 due to missing android.permission.DUMP permission	From `DumpUtils`, with the doubled `from from` that is genuine AOSP text, written to stdout in place of the dump. Piped into a `grep` for `topResumedActivity` it vanishes silently, and the result is indistinguishable from a phone whose screen is off. Check the unfiltered first line when a foreground-app query returns nothing.
* SERVICE 'activity' DUMP TIMEOUT (10000ms) EXPIRED *	Truncation matters more here than in most dumps. The resumed-activity lines are not at the top of the output, so a dump cut off at ten seconds can lose `topResumedActivity` while still containing plenty of task and stack text — which reads as "nothing is in the foreground" rather than as a partial answer. Raise the wait with `-t` before falling back to a weaker line such as `mCurrentFocus`.

Version and vendor notes

Field names here have been renamed twice and mirrored into other services, so match a set of spellings rather than one.
The binder work happens on the phone whether you filter or not; what filtering saves is the transfer, which over a cable is the part that scales with dump size.

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 dumpsys activity activities.

Command	What it does
am start	Starts an activity by component or by intent — the fastest way to test whether a deep link resolves.
am force-stop	Kills every process and service belonging to one app.
top	A one-shot process table: CPU share, memory, state and command line.

More System services (dumpsys) commands

Command	What it does
dumpsys battery	The battery service's live state: level, status, health, voltage and temperature.
dumpsys diskstats	Free space per partition, a disk write latency check, and a cached per-app breakdown of what is using storage.
dumpsys thermalservice	Whether the phone is throttling, and every thermal zone the hardware layer reports, in degrees Celsius.
dumpsys sensorservice	Every sensor the phone has, with its vendor, type, rates and batching — plus a buffer of recent readings.
dumpsys meminfo	Which processes are using the most memory, measured as proportional set size.
dumpsys package	Everything the package manager knows about one app: version, paths, flags, install source and per-user state.
dumpsys dropbox	The platform's ring buffer of crashes, ANRs and tombstones — how you read ANR traces without root.

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.