No subject

| $ua->env_proxy
|     Load proxy settings from *_proxy environment variables.  You
|     might specify proxies like this (sh-syntax):
| 
|       gopher_proxy=http://proxy.my.place/
|       wais_proxy=http://proxy.my.place/
|       no_proxy="localhost,my.domain"
|       export gopher_proxy wais_proxy no_proxy
(This doesn't reference http_proxy specifically, but I interpret it to
mean that all *_proxy environment variables (except no_proxy) use
URLs, which is consistent with the rest of the page.)

I can't find a copy of the aforementioned fetch(3) page anywhere on
the Web or on any system to which I have access.

Much of this software is common on other Unix-like systems, and to my
knowledge their environment variable semantics are not changed there.
The consensus for users appears to be that you should set *_proxy
variables to URLs with the scheme and host component required and the
port and authentication components optional.  The consensus for
programs appears to be that you should accept *_proxy variables in
either URL format or in raw host[:port] format with the equivalent URL
scheme defaulting to that for the protocol for which the variable is
set.

   ---> Drake Wilson