---
title: head — view the beginning of a file
date: 2026-10-18
time: 12:00
model: admin
category: programs
author_type: human
summary: A command to quickly check only the first few lines of a file. Useful for inspecting headers, configuration, and CSV files.
tags: program, server log recording and analysis, head
---

**💬 "head command"**

head displays the **first N lines** of a file. It is useful for checking the header of a formatted file.

Use it to quickly understand the structure before opening a large file.

- **Concept**: Prints the beginning of a file (10 lines by default).
- **Left argument**: Use -n number to specify the number of lines.
- **Right argument**: The target file.
- **Multiple files**: With multiple files, it shows the beginning of each file along with a per-file header.
## Commonly used options

| Option | Description |
| --- | --- |
| -n <N> | Prints the first N lines |
| -q | Suppresses file name headers when processing multiple files |
| -c <N> | Prints the first N bytes instead of lines |

## 3 essential command combinations

- `head -n 1 /var/log/nginx/access.log` — Check the format with the first log line
- `head -n 3 data.csv` — Check the first 3 CSV header lines
- `head -c 64 /opt/app/bin/app.bin | xxd | head` — Check the binary signature
**💬 "Give me an example from a security audit perspective"**

Here are common situations on a production server, organized in order.

### Step 1 · Check the format

Understand the structure with the first few lines of the file.

```
head -n 2 /etc/nginx/nginx.conf
```

### Step 2 · Compare samples

Compare the beginning of several files.

```
head -n 2 /var/log/nginx/*.log
```

### Step 3 · Check binary

View byte-level output if necessary.

```
head -c 32 /opt/app/bin/app | xxd
```

## How it is used in practice

### 1. Check CSV columns

**Situation** — You need to check the column order of an uploaded CSV first.

```
head -n 3 /srv/import/orders.csv
```

**Result** — Check the column order and delimiter with the header and two sample lines.

**Point** — Checking the format with head before writing an import script reduces trial and error.

### 2. Check the first block of a config file

**Situation** — You want to quickly see only the first structure among several server blocks.

```
head -n 20 /etc/nginx/nginx.conf
```

**Result** — Quickly understand the global settings and include structure.

**Point** — Use head to grasp the structure before opening the full file, then inspect in detail with less.

## Points to watch

- The default is 10 lines, so unless you specify the number of lines, you may not get enough information.
- If you set the number of lines too high, using head loses its purpose.
- If a CSV has fields containing line breaks, simple line counting will be off.
## Actual output

This is the result of checking the header and sample lines of a CSV file.

![head command output: CSV header and samples](https://games.aidebatehub.com/assets/head-demo.png)

Production server

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