DigitalOcean home. Community Control Panel. Hacktoberfest Contribute to Open Source. Launch an Interactive Terminal! About the authors. Brian Hogan. Instead, make curl save the incoming cookies using the well-known netscape cookie format like this:.
Note that by specifying -b you enable the "cookie awareness" and with -L you can make curl follow a location: which often is used in combination with cookies.
So that if a site sends cookies and a location, you can use a non-existing file to trigger the cookie awareness like:. Curl will determine what kind it is based on the file contents. In the above command, curl will parse the header and store the cookies received from www.
The file "empty. To read and write cookies from a netscape cookie file, you can set both -b and -c to use the same file:. The progress meter exists to show a user that something actually is happening. The different fields in the output have the following meaning:. The - option will display a totally different progress bar that does not need much explanation! Curl allows the user to set the transfer speed conditions that must be met to let the transfer keep going. By using the switch -y and -Y you can make curl abort transfers if the transfer speed is below the specified lowest limit for a specified time.
To have curl abort the download if the speed is slower than bytes per second for 1 minute, run:. This can be used in combination with the overall time limit, so that the above operation must be completed in whole within 30 minutes:. Forcing curl not to transfer data faster than a given rate is also possible, which might be useful if you are using a limited bandwidth connection and you do not want your transfer to use all of it sometimes referred to as "bandwidth throttle". When using the --limit-rate option, the transfer rate is regulated on a per-second basis, which will cause the total transfer speed to become lower than the given number.
Sometimes of course substantially lower, if your transfer stalls during periods. Curl automatically tries to read the. The config file could be made up with normal command line switches, but you can also specify the long options without the dashes to make it more readable.
Comments can be used within the file. If the first letter on a line is a -symbol the rest of the line is treated as a comment. If you want the parameter to contain spaces, you must enclose the entire parameter within double quotes ". Whitespaces ARE significant at the end of lines, but all whitespace leading up to the first characters of each line are ignored.
Prevent curl from reading the default file by using -q as the first command line parameter, like:. Force curl to get and display a local help page in case it is invoked without URL by making a config file similar to:. If you set config file name to - it will read the config from stdin, which can be handy if you want to hide options from being visible in process tables etc:. When using curl in your own programs, you may end up needing to pass on your own custom headers when getting a web page.
You can do this by using the -H flag. This can also be useful in case you want curl to send a different text in a header than it normally does. When connecting to a remote server that has a self signed certificate you will want to skip the ssl checks. To do this use the -k option. The -A option allows you to set the user agent. To avoid hitting the remote server hard you can limit the download rate you will use.
The command to do this is --limit-rate and use like this --limit-rate k. To download you just need to use the basic curl command but add your username and password like this curl --user username:password -o filename. To upload you need to use both the —user option and the -T option as follows. To delete a file from the remote server. The -X command allows you to send custom commands to the receiving server.
To have the text-based download information replaced by a simple progress bar, use the - progress bar option. It is easy to restart a download that has been terminated or interrupted. To restart the download, use the -C continue at option. This causes curl to restart the download at a specified point or offset within the target file. If you use a hyphen - as the offset, curl will look at the already downloaded portion of the file and determine the correct offset to use for itself.
Using xargs we can download multiple URLs at once. Perhaps we want to download a series of web pages that make up a single article or tutorial. This is the command we need to use to have xargs pass these URLs to curl one at a time:.
The -n 1 option tells xargs to treat each line of the text file as a single parameter. Checking in the file browser shows the multiple files have been downloaded. Each one bears the name it had on the remote server. Using curl with a File Transfer Protocol FTP server is easy, even if you have to authenticate with a username and password. This is a free-for-testing FTP server hosted by Rebex. Use the same command as a moment ago, with the filename appended to it:.
In almost all cases, it is going to be more convenient to have the retrieved file saved to disk for us, rather than displayed in the terminal window. Once more we can use the -O remote file output command to have the file saved to disk, with the same filename that it has on the remote server.
The file is retrieved and saved to disk. We can use ls to check the file details. It has the same name as the file on the FTP server, and it is the same length, bytes. Some remote servers will accept parameters in requests that are sent to them.
The parameters might be used to format the returned data, for example, or they may be used to select the exact data that the user wishes to retrieve. It is often possible to interact with web application programming interfaces APIs using curl. At the time of writing this article, the latest version is curl v7.
To demonstrate the usage of the curl program, first, we need a dummy file to download. Any online file will work for this, as long as you have the direct download link.
For this guide, I will use the small file provided by think broadband. This is a very basic way of using curl. We will download the dummy file.
With this flag, the file will be downloaded and saved at the current working directory. Need to download multiple files? Follow the command structure shown below.
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