linux - keep - sudo: sorry, you are not allowed to preserve the environment

How to keep environment variables when using sudo (3)

First you need to export HTTP_PROXY. Second, you need to read man sudo carefully, and pay attention to the -E flag. This works:

$ export HTTP_PROXY=foof
$ sudo -E bash -c 'echo $HTTP_PROXY'

Here is the quote from the man page:

-E, --preserve-env
             Indicates to the security policy that the user wishes to preserve their
             existing environment variables.  The security policy may return an error
             if the user does not have permission to preserve the environment.

When I use any command with sudo the environment variables are not there. For example after setting HTTP_PROXY the command wget works fine without sudo. However if I type sudo wget it says it can't bypass the proxy setting.

For individual variables you want to make available on a one off basis you can make it part of the command.

sudo http_proxy=$http_proxy wget "http://.com"

You can also combine the two env_keep statements in Ahmed Aswani's answer into a single statement like this:

Defaults env_keep += "http_proxy https_proxy"

You should also consider specifying env_keep for only a single command like this:

Defaults!/bin/[your_command] env_keep += "http_proxy https_proxy"