sudo add-apt-repository ppa:linaro-maintainers/toolchain

Error reading https://launchpad.net/api/1.0/~linaro-maintainers/+archive/toolchain: <urlopen error [Errno 110] Connection timed out>

$ set | grep -i proxy
HTTPS_PROXY=https://gateway:8080
HTTP_PROXY=http://gateway:8080
http_proxy=http://gateway:8080
https_proxy=https://gateway:8080

$ set | grep -i proxy
HTTPS_PROXY=gateway:8080
HTTP_PROXY=gateway:8080
http_proxy=gateway:8080
https_proxy=gateway:8080

Acquire::http::proxy "http://gateway:8080/";
Acquire::https::proxy "https://gateway:8080/";

$ sudo add-apt-repository ppa:linaro-maintainers/toolchain
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver keyserver.ubuntu.com --recv 1DD749B890A6F66D050D985CF1FCBACA7BE1F97B
gpg: requesting key 7BE1F97B from hkp server keyserver.ubuntu.com
gpgkeys: HTTP fetch error 7: couldn't connect to host
gpg: no valid OpenPGP data found.
gpg: Total number processed: 0

Defaults env_keep="http_proxy"
Defaults env_keep="https_proxy"

$ sudo env | grep proxy
https_proxy=https://gateway:8080

$ sudo add-apt-repository ppa:linaro-maintainers/toolchain
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver keyserver.ubuntu.com --recv 1DD749B890A6F66D050D985CF1FCBACA7BE1F97B
gpg: requesting key 7BE1F97B from hkp server keyserver.ubuntu.com
gpg: key 7BE1F97B: public key "Launchpad Linaro Overlay PPA" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)

export http_proxy=http://<proxy>:<port>
export https_proxy=http://<proxy>:<port>
sudo -E add-apt-repository ppa:linaro-maintainers/toolchain

export https_proxy=https://<username>:<password>@<proxy>:<port>

sudo apt-key adv --keyserver-options http-proxy=http://USER:PASSWORD@PROXY_URL:PORT/ --keyserver keyserver.ubuntu.com --recv-keys GPG_KEY

sudo apt-key adv --keyserver-options http-proxy=http://user:abc123@10.10.2.21:3128/ --keyserver keyserver.ubuntu.com --recv-keys C2514567EEA14886

USER_ID=user
PASSWORD=abc123
PROXY_URL=10.10.2.21
PORT=3128

sudo apt-key adv --keyserver-options http-proxy=http://10.10.2.21:3128/ --keyserver keyserver.ubuntu.com --recv-keys C2514567EEA14886

export https_proxy=....

sudo su
add-apt-repository ppa:........

apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys XXXXX

Defaults env_keep="http_proxy"
    Defaults env_keep="https_proxy"

Defaults env_keep+="http_proxy"
    Defaults env_keep+="https_proxy"

sudo https_proxy='https://user:password@proxyhost:port/'
http_proxy='http://user:password@proxyhost:port/'
ftp_proxy='ftp://user:password@proxyhost:port/'
no_proxy=localhost,127.0.0.0/8,10.0.0.0/8 add-apt-repository ppa:webupd8team/java

export http_proxy=http://username:password@proxyserver.net:port/
export ftp_proxy=http://username:password@proxyserver.netport/

deb http://ppa.launchpad.net/<user>/<repo>/ubuntu trusty main

W: GPG error: http://ppa.launchpad.net trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5BB92C09DB82666C

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 5BB92C09DB82666C

"--keyserver-options", "http-proxy=<proxy_url>",

"--keyserver", self.keyserver,