Using of cURL

I found some useful use of cURL in this article.
http://www.semicomplete.com/blog/geekery/ssl-latency.html
So, I collect the sample commands here.


% fping -q -c 5 http://www.csh.rit.edu
http://www.csh.rit.edu : xmt/rcv/%loss = 5/5/0%, min/avg/max = 112/115/123

% seq 5 | xargs -I@ -n1 curl -so /dev/null -w "%{time_connect}\n" http://www.csh.rit.edu
0.117
0.116
0.117
0.116
0.116

% curl -kso /dev/null -w "tcp:%{time_connect}, ssldone:%{time_appconnect}\n" https://www.csh.rit.edu
tcp:0.117, ssldone:0.408

terminal1 % sudo tcpdump -ttttt -i any 'port 443 and host http://www.csh.rit.edu'
...

terminal2 % openssl s_client -connect http://www.csh.rit.edu:443
...

Tcpdump output trimmed for content:

# Start TCP Handshake
00:00:00.000000 IP snack.home.40855 > csh.rit.edu.https: Flags [S] ...
00:00:00.114298 IP csh.rit.edu.https > snack.home.40855: Flags [S.] ...
00:00:00.114341 IP snack.home.40855 > csh.rit.edu.https: Flags [.] ...
# TCP Handshake complete.

# Start SSL Handshake.
00:00:00.114769 IP snack.home.40855 > csh.rit.edu.https: Flags [P.] ...
00:00:00.226456 IP csh.rit.edu.https > snack.home.40855: Flags [.] ...
00:00:00.261945 IP csh.rit.edu.https > snack.home.40855: Flags [.] ...
00:00:00.261960 IP csh.rit.edu.https > snack.home.40855: Flags [P.] ...
00:00:00.261985 IP snack.home.40855 > csh.rit.edu.https: Flags [.] ...
00:00:00.261998 IP snack.home.40855 > csh.rit.edu.https: Flags [.] ...
00:00:00.273284 IP snack.home.40855 > csh.rit.edu.https: Flags [P.] ...
00:00:00.398473 IP csh.rit.edu.https > snack.home.40855: Flags [P.] ...
00:00:00.436372 IP snack.home.40855 > csh.rit.edu.https: Flags [.] ...

# SSL handshake complete, ready to send HTTP request.
# At this point, openssl s_client is sitting waiting for you to type something
# into stdin.

% URL=https://s-static.ak.facebook.com/rsrc.php/zPET4/hash/9e65hu86.js
% curl -w "tcp: %{time_connect} ssl:%{time_appconnect}\n" -sk -o /dev/null $URL -o /dev/null $URL
tcp: 0.038 ssl:0.088
tcp: 0.000 ssl:0.000

% URL=https://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js
% curl -w "tcp: %{time_connect} ssl:%{time_appconnect}\n" -sk -o /dev/null $URL -o /dev/null $URL
tcp: 0.054 ssl:0.132
tcp: 0.000 ssl:0.000

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