curl question - not exactly on-topic

Dan Nelson dnelson at
Wed Feb 10 05:05:20 UTC 2010

In the last episode (Feb 09), Kurt Buff said:
> Actually, it's not merely a curl question, it's a "curl and squid"
> question.
> I'm trying to determine the cause of a major slowdown in web browsing on
> our network, so I've put curl on the squid box, and am using the following
> incantations to see if I can determine the cause of the slowdown:
>   curl -s -w "%{time_total}\n" "%{time_namelookup}\n" -o /dev/null
> and
>   curl -s -w "%{time_total}\n" "%{time_namelookup}\n" -o /dev/null -x
> The problem arises with the second version, which uses the proxy. The
> first incantation just returns the times, which is exactly what I want.
> However, when I use the -x parameter, to use the proxy, I get html
> returned as well as the times, which is a pain to separate out.

Your problem is what's after -w.  You want one argument:
"%{time_total}\n%{time_namelookup}\n", not two.  With your original command,
"%{time_namelookup}\n" is treated as another URL to fetch.  With no proxy
option, curl realizes it's not an url immediately and skips to the next
argument on the commandline -  With a proxy, curl
has to send each url to the proxy for processing.  The proxy probably
returns a "400 Bad Request" error on the first (invalid) url, which is
redirected to /dev/null.  The next url doesn't have another -o so it falls
back to printing to stdout.

Adding -v to the curl commandline will help you diagnose problems like this.

	Dan Nelson
	dnelson at

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