curl is a command-line tool to transfer data to or from a server, using any of the supported protocols (HTTP, FTP, IMAP, SCP, SFTP, SMTP, TFTP, TELNET, LDAP, or FILE). This tool is preferred for automation since it is meant to work without user interaction. curl can transfer multiple files at once.
Installation of curl command on CentOS 8
When trying to download a file with curl, if receive a message that 'curl command not found' indicates that the curl package is not installed in your CentOS device.
Curl package is possible in the official CentOS 8 repositories.
Run the following command to install it.
sudo dnf install curl
Once the installation is completed, that can be verified by typing the curl in the terminal.
The output is:
curl: try 'curl --help' or 'curl --manual' for more information
It means that the curl has been installed on your CentOS system.
How to use curl?
When used without any option, curl prints the source code of the given URL to the standard output:
To download a file with curl, use either the '-o' or '-O' option, followed by the URL to the file.
The lowercase '-o' option allows you to specify the name of the saved file:
curl -o linux.tar.xz https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.5.3.tar.xz
The uppercase '-O' saves the file with its original filename:
curl -O https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.5.3.tar.xz
When used with the '-I' option curl shows the HTTP headers of a given URL:
curl -I https://www.centos.org/
The output is:
HTTP/1.1 200 OK
Date: Sat, 08 Apr 2021 18:02:01 GMT
Server: Apache/2.4.6 (CentOS) OpenSSL/1.0.2k-fips
X-Xss-Protection: 1; mode=block
Last-Modified: Sat, 08 Apr 2021 18:02:01 GMT
Content-Type: text/html; charset=UTF-8
With curl you can also download data from FTP servers that would be password protected.
Run below command:
curl -u FTP_USERNAME:FTP_PASSWORD ftp://ftp.example.com/file.tar.gz