---
title: top — Real-time process status
date: 2026-10-18
time: 12:00
model: admin
category: programs
author_type: human
summary: A basic tool that shows the top processes by CPU and memory usage in real time. The starting point for identifying the cause of load.
tags: program, Service and process management, top
---

**💬 "top command"**

top shows **system load and processes in real time**. This is the first screen to check when something seems wrong.

You can see load average, CPU usage, memory, and top processes at a glance.

- **load average**: Average load over 1/5/15 minutes. Compare it with the number of CPU cores to interpret it.
- **%Cpu(s)**: The share of user/system/iowait. If iowait is high, it's a disk bottleneck.
- **MiB Mem**: Total/used/free memory. If free is close to 0, it's dangerous.
- **Process list**: Top CPU or memory processes are displayed.
## Frequently used options

| Option | Description |
| --- | --- |
| -H | Display by thread |
| -u <user> | View only a specific user's processes |
| -b -n 1 | Output only once (for scripts/collection) |
| -o %MEM | Sort by memory |

## Three essential command combinations

- `top -b -n 1 | head -15` — Capture current state once
- `top -o %CPU -b -n 1 | head -20` — Check top CPU-consuming processes
- `top -u www-data -b -n 1 | head` — View only web server account processes
**💬 "Tell me how to use it together with monitoring"**

Here are common situations on production servers, organized in order.

### Step 1 · Check overall load

Check load average and CPU/memory status.

```
top -b -n 1 | head -5
```

### Step 2 · Identify the culprit process

Check the top CPU/memory processes.

```
top -o %CPU -b -n 1 | head -12
```

### Step 3 · Further inspection

Look at the details of that process.

```
ps -o pid,ppid,%cpu,%mem,etime,cmd -p <PID>
```

## How it's used in practice

### 1. Slow server response

**Situation** — Web response suddenly became slow.

```
top -b -n 1 | head -5
```

**Result** — If load average is significantly higher than the number of cores or iowait is high, you can narrow down the cause.

**Point** — Even if load is high, if the CPU is idle it may be I/O wait, so check %Cpu(s) as well.

### 2. Running low on memory

**Situation** — You're worried about OOM.

```
top -o %MEM -b -n 1 | head -12
```

**Result** — Find processes using a lot of memory and consider limiting or restarting them.

**Point** — Check with free -h and also verify whether swap is being used.

## Things to watch out for

- Since top refreshes in real time, use -b -n 1 to print only once in scripts.
- Load average should be interpreted relative to core count (for example, on 8 cores, 8 means saturation).
- Because it is a momentary snapshot, it can miss short spikes, so repeated collection may be necessary.
## Actual execution screen

This is the result of checking load average and CPU/memory status.

![top command execution result: system load and processes](https://games.aidebatehub.com/assets/top-demo.png)

Production server

---
Source (HTML): https://games.aidebatehub.com/programs/linux/services/top.html
This file is an auto-generated Markdown twin of the DevHub document.