---
title: curl Command Cheatsheet
description: "# Guide to the `curl` Command in Linux The `curl` command is a versatile tool in Linux used for transferring data to or from a server. It supports various protocols, including HTTP, HTTPS, FTP, and others, and is particularly useful…"
url: "https://www.relianoid.com/resources/knowledge-base/misc/curl-command-cheatsheet/"
updated: "2025-05-27"
category: Misc
---

# curl Command Cheatsheet

# Guide to the `curl` Command in Linux

The `curl` command is a versatile tool in Linux used for transferring data to or from a server. It supports various protocols, including HTTP, HTTPS, FTP, and others, and is particularly useful for API testing and downloading files.

## Basic Syntax of the `curl` Command

The command syntax is as follows:

`curl [OPTIONS] URL`

- **OPTIONS**: Flags to modify the command’s behavior, such as setting headers, specifying request methods, or saving output to a file.
- **URL**: The web address to which `curl` will send a request or from which it will retrieve data.

## Option Table for the `curl` Command

| Option | Description |
| --- | --- |
| `-o FILE` | Saves the output to a specified file (e.g., `curl -o page.html http://example.com` saves the content to `page.html`). |
| `-O` | Uses the remote file name and saves it locally (e.g., `curl -O http://example.com/image.jpg` saves the file as `image.jpg`). |
| `-L` | Follows redirects (useful for URLs that redirect to other locations). |
| `-I` | Fetches only the HTTP headers without the body (useful for getting metadata). |
| `-X METHOD` | Specifies the HTTP method to use, such as `GET`, `POST`, `DELETE` (e.g., `curl -X POST http://example.com`). |
| `-H "Header: Value"` | Adds a custom header to the request (e.g., `curl -H "Authorization: Bearer token" http://example.com`). |
| `-d "data"` | Sends data with the request (commonly used with POST requests). |
| `-u USER:PASS` | Sets basic authentication (e.g., `curl -u admin:password http://example.com`). |

## Examples of Using the `curl` Command

Here are some common examples of the `curl` command in use:

### Download a File

`curl -O http://example.com/file.zip`

This command downloads `file.zip` from `http://example.com` and saves it with the same name.

### Save Output to a File

`curl -o mypage.html http://example.com`

Saves the output from `http://example.com` to a local file named `mypage.html`.

### Follow Redirects

`curl -L http://example.com`

Follows any redirects from the original URL to the final destination.

### Retrieve HTTP Headers Only

`curl -I http://example.com`

Fetches and displays only the HTTP headers from the URL, omitting the response body.

### Send Data with POST Request

`curl -X POST -d "name=John&age=30" http://example.com/api`

Sends data in the body of a POST request to `http://example.com/api`.

### Add Custom Headers

`curl -H "Content-Type: application/json" -H "Authorization: Bearer token" http://example.com`

Sets custom headers in the request, useful for specifying content types or authorization tokens.

## Interpreting `curl` Output

When using `curl`, the output generally includes the following:

- **Response Body**: The content of the requested page or data, unless options suppress or redirect it.
- **Headers**: HTTP headers are included if requested with `-I` or when troubleshooting HTTP status codes.
- **Progress Meter**: Displays the download or upload progress if the data transfer is large.

## Summary

The `curl` command is an essential Linux tool for web and API interactions, supporting numerous options for managing headers, data payloads, request methods, and more. It's a powerful utility for downloading files, testing APIs, and checking server responses.

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