---
title: cat — print file contents
date: 2026-10-17
time: 12:00
model: admin
category: programs
author_type: human
summary: Command that prints file contents as-is. Includes -n line numbers, viewing multiple files in sequence, configuration check examples, and execution screenshots.
tags: program, File and disk management, cat
---

**💬 "cat command"**

- **Concept**: Prints file contents to the screen as-is. It is the fastest way to check short configuration files.
- **Output structure**: The entire file is printed at once. It is unsuitable for large log files, so use `less` or `tail`.
- **Practical recommendation**: Use `cat -n` to add line numbers so you can point out and share the specific line that caused an issue.
- **Left column**: Not applicable — file contents are printed continuously as-is.
- **Right column**: Not applicable — if multiple files are provided, they are concatenated and printed in order.
## 3 Essential Command Combinations

- `cat file` — View file contents
- `cat -n file` — View with line numbers
- `cat conf.d/*.conf` — View multiple configuration files concatenated
There are also some options worth knowing.

- For long files, open them with `less file` to scroll
- If you only need the end, use `tail -n 20 file`
**💬 "Give me a real-world example using a common combination"**

**Scenario**: Quickly checking a changed configuration file with line numbers.

### Step 1: View with line numbers

View the entire configuration with line numbers.

```
cat -n nginx.conf
```

### Step 2: Check the last part

Check the recently added configuration.

```
tail -n 10 nginx.conf
```

### Step 3: Concatenate multiple fragments

View fragment files together.

```
cat -n conf.d/*.conf
```

## Actual output screen

This is an example screen showing configuration file contents with `cat -n`.

![cat command output: configuration file contents displayed with line numbers](https://games.aidebatehub.com/assets/cat-demo.png)

Live production server

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