apt lock

ps aux | grep -i apt

$ sudo dpkg --configure -a
dpkg: error: parsing file '/var/lib/dpkg/updates/0004' near line 0:
newline in field name '#padding'

rm -rf /var/cache/apt/* /var/lib/dpkg/lock /var/lib/dpkg/lock-frontend \
/var/cache/debconf/ /var/lib/apt/lists/* \
/var/lib/dpkg/lock /var/lib/dpkg/lock-frontend /var/cache/debconf/