# tail -f /var/log/unattended-upgrades/unattended-upgrades.log
2018-02-18 13:25:37,656 DEBUG No conffiles in deb
'/var/cache/apt/archives/libgfortran3_4.9.2-10+deb8u1_amd64.deb' (There
is no member named 'conffiles')
2018-02-18 13:25:37,657 DEBUG blacklist: []
2018-02-18 13:25:37,658 DEBUG whitelist: []
2018-02-18 13:25:37,658 DEBUG InstCount=23 DelCount=0 BrokenCount=0
2018-02-18 13:25:37,660 INFO Packages that will be upgraded: cpp-4.9
g++-4.9 gcc-4.9 gcc-4.9-base gcc-4.9-base:i386 libasan1 libatomic1
libcilkrts5 libgcc-4.9-dev libgcc1 libgcc1:i386 libgfortran3 libgomp1
libitm1 liblsan0 libobjc-4.9-dev libobjc4 libquadmath0 libstdc++-4.9-dev
libstdc++6 libstdc++6:i386 libtsan0 libubsan0
2018-02-18 13:25:37,662 INFO Writing dpkg log to '/var/log/unattended-
upgrades/unattended-upgrades-dpkg.log'
2018-02-18 13:27:02,483 INFO All upgrades installed
2018-02-18 13:27:02,485 DEBUG Extracting content from
'/var/log/unattended-upgrades/unattended-upgrades-dpkg.log' since '2018-
02-18 13:25:37.661632'
2018-02-18 13:27:02,511 DEBUG Sending mail to 'xxxyyyy@gmail.com'
2018-02-18 13:27:02,713 DEBUG mail returned: 0


# cat /etc/apt/listchanges.conf
[apt]
frontend=pager
email_address=xxxyyyy@gmail.com
confirm=0
save_seen=/var/lib/apt/listchanges.db
which=news

$ echo "Just testing mailx" | mail -s "Yooo woot" xxxyyyy@gmail.com