Top 20 Curl Flags

Curl supports over 380 command-line flags that can be used to customize every aspect of Curl. Curl is designed to work without user interaction, supports many popular Internet protocols, and runs on most modern operating systems. Curl's possibilities are endless, and it is easy to get lost in many flags. This article provides a list of the most commonly used Curl flags with short descriptions that you can use in your projects.
Top 20 Curl Flags Run
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What is Curl?

Curl is a command-line utility for Linux, Windows, and Mac that provides basic URL handling and file transfer capabilities. Curl supports the following protocols: FTP, FTPS, HTTP, HTTPS, TFTP, SCP, SFTP, Telnet, DICT, LDAP, POP3, IMAP, and SMTP. Curl is great for mimicking user actions on pages, testing APIs, and other URL operations, have built-in support for SSL, proxies, certificate validation, HTTP cookies, and user authentication.

What is a flag in Curl?

A flag is a command-line parameter that denotes a specific action in Curl. Curl has over three hundred command-line options, and the number of options increases over time. You can add the listed flags to the Curl command and enter the URL. Flags can be short (like o, -L, etc.) or extended (like --verbose). Flags are available with single or double dashes.

How can I see the list of parameters in Curl?

To determine which parameters you need to use as a specific action, you can force Curl to enumerate them. First, the Curl --help or -h command will give you a list of the most important and commonly used options. Use curl -h [category] to list all existing types, or curl -h [all] to list all available options. Curl can combine commands by adding the listed flags and entering the URL.

Curl Help
curl --help
curl -h

List of all Curl commands
curl -h [category]

All available Curl parameters
curl -h [all]

20 most popular Curl flags for everyday use

The table below does not show all of the Curl options, but some of them you will use in your projects.

Flags Description Syntax
-O Download the file and save it under the original name
curl -O [URL]
-o Download the file and save it with a different name
curl -o [file name] [URL]
-X Specify the HTTP method to be used when sending the request
curl -X [method] [URL]
-I or -head Print the title without the body of the document
curl -I [URL]
-d Specify the data to send to the server
curl -d "key1=value1&key2=value2" [URL]
-k or -insecure Ignore SSL Certificate Errors
curl -k [URL]
-u or --user Specify the authentication data by passing a pair of login-password
curl -u [user:password] [URL]
-F Submit form data as POST request
curl -F @[email protected]/to/myFile
--cookie Send HTTP cookies
curl --cookie "Name=Value" [URL]
-x or --proxy Use a proxy server to upload files
curl -x "[protocol://][host][:port]" [URL] [options]
--limit-rate Limit the download speed
curl --limit-rate [speed] -O [URL]
-L or --location Follow Curl redirect using HTTP Location header
curl -L [URL]
-v Makes Curl verbose
curl -v [URL]
-m or --max-time Set a limit in seconds for the entire operation
curl -m [SECONDS] [URL]
--connect-timeout Set a limit in seconds for a connection request
curl --connect-timeout [SECONDS] [URL]
-T Transfers the specified local file to a remote URL
curl -T [file name] [URL]
-H or --header Add additional HTTP request header
curl -H "X-Header: value" [URL]
-D Save the HTTP headers that the site sends back
curl -D [URL]
-A or --user-agent Set User-Agent string
curl -A "value" [URL]
-C Resume an interrupted or intentionally stopped download
curl -C [OFFSET] -O [URL]

Conclusion

Curl is a powerful command-line tool compatible with almost all operating systems and connected devices. Curl is helpful for API testing, has detailed information about what was sent/received to the server, and has good error logging. Only the basic flags are shown in the article as they offer many more options. When you're done practicing the command line flags described in this tutorial, you can head over to the Curl man page to learn about all of the flag capabilities.

See also

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