The --form option in Curl is used for HTTP multipart POST operations, which is particularly useful when you're providing large amounts of data to the server, such as when you're uploading files or submitting forms with complex data.
When you use the --form option with Curl, you're telling it to send data to the server using the multipart/form-data method. This is the same method that's used when a form is submitted on a web page.
The --form option also allows you to specify the content type and file name for uploaded files, and you can even specify multiple --form options to upload multiple files or send multiple fields in the same request.
Here's a basic example of using the --form option to upload a file:
curl --form "fileupload=@my-file.txt" http://myserver.com/upload
In this example, the @ symbol tells Curl that this is a file upload field. The file my-file.txt is read from the current directory and uploaded to the server. The name of the form field (fileupload in this case) is often specified by the website or API that you're interacting with.
Here's another example that includes multiple fields:
curl --form "username=myusername" --form "password=mypassword" --form "fileupload=@my-file.txt" http://myserver.com/upload
In this example, we're sending two regular fields (username and password) along with the file upload.
The --form option is very powerful, but it's also somewhat complex due to the variety of options and formats it supports. For more detailed information, you can check out the Curl man page or other online resources.
