apt-get update

• apt-get update

apt-get install
apt-get upgrade

To select specific repositories:

find /etc/apt/sources.list.d -type f -name '*.list' -exec sudo apt-get update -o Dir::Etc::sourcelist="{}" ';'

apt-get update -o Dir::Etc::sourcelist=/etc/apt/sources.list.d/avalanche.list

apt-cache

The following signatures were invalid

W: Some index files failed to download. They have been ignored, or old ones used instead.

 FROM ubuntu:20.04 
RUN apt-get update \
    && apt-get install -y --no-install-recommends mysql-client \
    && rm -rf /var/lib/apt/lists/*
ENTRYPOINT ["mysql"]

Related

• apt-get upgrade
• apt update
• RUN

See also

• apt-get [ install | upgrade | update | source ], /etc/apt/sources.list
• APT: wajig, apt-cache, add-apt-repository PPA, apt [ install | remove |purge | show | list | changelog | update | upgrade], do-release-upgrade, apt-mark, apt full-upgrade, sources.list, APT Automatic updates, unattended-upgrade, apt-transport-https, apt-get update, /etc/apt/, /etc/apt/apt.conf.d/50unattended-upgrades, /etc/apt/apt.conf.d/, /etc/apt/apt.conf.d/20auto-upgrades, apt-file, apt-utils