curl.1: mention how to add numerical IP addresses in NO_PROXY

list of host names that shouldn't go through any proxy. If set to a asterisk

\&'*' only, it matches all hosts.

Since 7.53.0, this environment variable disable the proxy even if specify

--proxy option. That is

This environment variable disables use of the proxy even when specified with

the --proxy option. That is

.B NO_PROXY=direct.example.com curl -x http://proxy.example.com

.B http://direct.example.com

accesses the target URL directly, and

.B NO_PROXY=direct.example.com curl -x http://proxy.example.com

.B http://somewhere.example.com

accesses the target URL through proxy.

accesses the target URL through the proxy.

The list of host names can also be include numerical IP addresses, and IPv6

versions should then be given without enclosing brackets.

.SH "PROXY PROTOCOL PREFIXES"

Since curl version 7.21.7, the proxy string may be specified with a