HTTP requests can be initiated in shell scripts using curl or wget. 1. curl supports multiple protocols and custom request headers, which is suitable for processing JSON data and controlling request details; 2. wget is more suitable for downloading files or the entire website, and supports breakpoint continuous transmission; 3. Both can initiate GET and POST requests, but curl is more flexible when handling complex API requests; 4. Select the appropriate tool according to environmental support and specific needs.

Directly answer the title question: You can use curl or wget in shell scripts to initiate HTTP requests. Both support common GET, POST and other methods, suitable for automated tasks or debugging APIs.

Use curl to initiate basic HTTP requests

curl is a powerful command line tool that is often used to transfer data. It supports a variety of protocols, including HTTP, HTTPS, FTP, etc.

The simplest example of GET request:

 curl https://example.com

If you want it to run more quietly in the script, you can add the -s parameter:

 curl -s https://example.com

If you need to send a POST request, such as submitting data to the API, you can write it like this:

 curl -X POST -d "param1=value1&param2=value2" https://api.example.com/endpoint

Common usages include:

• Add request header: -H "Content-Type: application/json"
• Send JSON data: -d '{"key":"value"}'
• Automatic follow redirection: -L

Use wget to get web content or download files

wget is more inclined to download files and crawl web page content recursively, but it can also be used for HTTP requests in some scenarios.

For example, initiate a simple GET request and save the response content to a file:

 wget -O output.txt https://example.com

If you just want to test whether the request is successful and not save the result, you can add a -q parameter to make wget quieter:

 wget -q --spider https://example.com

Note: --spider mode does not really download content, it just checks whether the link exists.

To send a POST request, it can also be done, but the syntax is a little more complicated:

 wget --post-data "param1=value1&param2=value2" -O response.txt https://api.example.com/endpoint

Choose curl or wget?

Both tools can complete basic HTTP requests, but each has its own advantages in different scenarios:

• Case of preferential curl:

  • Custom request headers are required (such as adding authentication information)
  • Need to process data in JSON, XML and other formats
  • I hope to control request details, such as timeout, SSL verification, etc.
  • Parsing the return value in the script for the next step of judgment

• Preferred wget:

  • Just want to download files or the entire website
  • Requires breakpoint continuous transmission function
  • Don't care much about the request details, just focus on whether the results can be saved

Some systems have one of them installed by default without the other, so it is best to confirm whether the environment supports it.

Basically that's it. Select the right tool according to your specific needs, and then adjust the parameters as needed. What is not complicated but easy to ignore is paying attention to the request method, data format and error handling.

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