这里记录下来备用。

nano /etc/apt/sources.list

# deb https://deb.debian.org/debian bullseye main

deb https://deb.debian.org/debian bullseye main
deb-src https://deb.debian.org/debian bullseye main

deb https://deb.debian.org/debian-security bullseye-security main
deb-src https://deb.debian.org/debian-security bullseye-security main

# bullseye-updates, to get updates before a point release is made;
# see https://www.debian.org/doc/manuals/debian-reference/ch02.en.html#_updates_and_backports
deb https://deb.debian.org/debian bullseye-updates main
deb-src https://deb.debian.org/debian bullseye-updates main

# bullseye-backports, previously on backports.debian.org
deb https://deb.debian.org/debian bullseye-backports main
deb-src https://deb.debian.org/debian bullseye-backports main