I am experiencing the same problem after a 14.04 -> 16.04 update:
'apt update' fails with ".. Could not execute 'apt-key' to verify signature (is gnupg installed?)"
but chattring /tmp +a (to keep the files) and executing the same apt-key commands gotten from 'apt-get -o "Debug::Acquire::gpgv=true" update' (albeit with --status-fd pointing to /dev/stderr) works!
Right now my system is totally unable to update !
I am experiencing the same problem after a 14.04 -> 16.04 update: :Acquire: :gpgv=true" update' (albeit with --status-fd pointing to /dev/stderr) works!
'apt update' fails with ".. Could not execute 'apt-key' to verify signature (is gnupg installed?)"
but chattring /tmp +a (to keep the files) and executing the same apt-key commands gotten from 'apt-get -o "Debug:
Right now my system is totally unable to update !