Fixing the GPG missing keys error

Sometimes we face the missing gpg key issue when we add diffrent sources to sources.list files, well this can be fixed easily:
Im gonna show an example where im using ubuntu 14 and try to first add sources of debian jessie 8.

first go to http://debgen.simplylinux.ch/

get your source list, for eg:

deb http://ftp.us.debian.org/debian testing main contrib non-free
deb-src http://ftp.us.debian.org/debian testing main contrib non-free

deb http://security.debian.org/ jessie/updates main contrib non-free
deb-src http://security.debian.org/ jessie/updates main contrib non-free

paste this in

nano /etc/apt/sources.list

then run this script:

#!/bin/bash

apt-get update 2> /tmp/keymissing; for key in $(grep "NO_PUBKEY" /tmp/keymissing |sed "s/.*NO_PUBKEY //"); do echo -e "\nProcessing key: $key"; gpg --keyserver pgpkeys.mit.edu --recv $key && gpg --export --armor $key | apt-key add -; done
apt-get update 2> /tmp/keymissing; for key in $(grep "NO_PUBKEY" /tmp/keymissing |sed "s/.*NO_PUBKEY //"); do echo -e "\nProcessing key: $key"; gpg --keyserver subkeys.pgp.net --recv $key && gpg --export --armor $key | apt-key add -; done

# it works if the command finished and says things like:
#  gpg: requesting key 46925553 from hkp server pgpkeys.mit.edu
#  gpg: key 46925553: "Debian Archive Automatic Signing Key (7.0/wheezy)
#  <ftpmaster@debian.org>" not changed
#  gpg: Total number processed: 1
#  gpg:              unchanged: 1

# If doesnt work and stuck on
# gpg: requesting key 46925553 from hkp server pgpkeys.mit.edu

# Then copy key from this line
# "Processing key: 8B48AD6246925553"
# and google search "8B48AD6246925553" this will return keyserver, like below, put those in for --keyserver line

# And look for keyserver

# Works for debian: pgpkeys.mit.edu
# Works for ubuntu: subkeys.pgp.net

This will work for both, ubuntu and debian - vice versa.

Special thanks to :  http://ram.kossboss.com/fix-missing-gpg-key-apt-get/