Hi Patrick,
I believe that nitass was just showing you the entire example of the Virtual Server that he used to apply the test iRule to, the test iRule itself, and then a successful test of the iRule using curl.
curl is a tool to transfer data from or to a server, using one of the supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP,
SCP, SFTP, SMTP, SMTPS, TELNET and TFTP). The command is designed to work without user interaction.
The -I option Fetch the HTTP-header only! HTTP-servers feature the command HEAD which this uses to get nothing but the header of a document. When used on a FTP or FILE file, curl displays
the file size and last modification time only.
You can find out more about curl here:
curl
Hope this helps.