transfer a URL

-s, --silent
       Silent or quiet mode. Don't show progress meter or error messages.  Makes Curl mute.

-f, --fail
       (HTTP)  Fail  silently  (no  output at all) on server errors. This is mostly done to better enable
       scripts etc to better deal with failed attempts. In normal cases  when  a  HTTP  server  fails  to
       deliver  a  document,  it  returns an HTML document stating so (which often also describes why and
       more). This flag will prevent curl from outputting that and return error 22.

       This method is not fail-safe and there are occasions where non-successful response codes will slip
       through, especially when authentication is involved (response codes 401 and 407).

-a, --append
       (FTP/SFTP)  When  used  in  an upload, this will tell curl to append to the target file instead of
       overwriting it. If the file doesn't exist, it will be created.  Note that this flag is ignored  by
       some SSH servers (including OpenSSH).

-t, --telnet-option <OPT=val>
       Pass options to the telnet protocol. Supported options are:

       TTYPE=<term> Sets the terminal type.

       XDISPLOC=<X display> Sets the X display location.

       NEW_ENV=<var,val> Sets an environment variable.