add-apt-repository use behind proxy

[add-apt-repository use behind proxy]


1. Prerequisite

    1) proxy server address.
        ex) proxy.firewall.com:8080

    2) proxy server certificate.
        ex) sslproxy.crt

2. Instruction

    Add proxy server certificate to the end of ca-certificates.crt file.
    $ sudo vi /etc/ssl/certs/ca-certificates.crt

    $ export HTTPS_PROXY=https://proxy.firewall.com:8080
    $ export HTTP_PROXY=http://proxy.firewall.com:8080
    $ export http_proxy=http://proxy.firewall.com:8080
    $ export https_proxy=proxy.firewall.com:8080

    $ sudo -E add-apt-repository ppa:igloocommunity-maintainers/snowball-tools
    ~~~
    ~~~
    gpg: requesting key 4AEF2843 from hkp server keyserver.ubuntu.com
    gpg: key 4AEF2843: public key "Launchpad PPA for IglooCommunity Maintainers" imported
    gpg: Total number processed: 1
    gpg:               imported: 1  (RSA: 1)

    $ sudo apt-get update
    $ sudo apt-get install riff