http://d.hatena.ne.jp/akuwano/20120503/1335994486
を実際にやってみた

root@hostname:/home/shimizu# vi /tmp/curl_env.txt
======
url_effective\t\t: %{url_effective}\n
http_code\t\t: %{http_code}\n
http_connect\t\t: %{http_connect}\n
time_total\t\t: %{time_total}\n
time_namelookup\t\t: %{time_namelookup}\n
time_connect\t\t: %{time_connect}\n
time_appconnect\t\t: %{time_appconnect}\n
time_pretransfer\t\t: %{time_pretransfer}\n
time_redirect\t\t: %{time_redirect}\n
time_starttransfer\t\t: %{time_starttransfer}\n
size_download\t\t: %{size_download}\n
size_upload\t\t: %{size_upload}\n
size_header\t\t: %{size_header}\n
size_request\t\t: %{size_request}\n
speed_download\t\t: %{speed_download}\n
speed_upload\t\t: %{speed_upload}\n
======

root@hostname:/home/shimizu# curl  -o /dev/null http://tech.akat.info/ -w @/tmp/curl_env.txt -s
url_effective           : http://tech.akat.info/
http_code               : 200
http_connect            : 000
time_total              : 0.269
time_namelookup         : 0.077
time_connect            : 0.090
time_appconnect         : 0.000
time_pretransfer                : 0.090
time_redirect           : 0.000
time_starttransfer              : 0.243
size_download           : 15680
size_upload             : 0
size_header             : 258
size_request            : 78
speed_download          : 58188.000
speed_upload            : 0.000