Ubuntu – Why is there a minus sign instead of a check mark in the software sources configuration window

software-sources

After an initial installation of Ubuntu, the software sources window has check marks on main, universe, restricted, and multiverse, but a minus sign on source code.

Software Sources window

Nevertheless, all deb-src lines in /etc/apt/sources.list are uncommented.

What is the difference to explicitly selecting the checkbox?

Best Answer

It means that not all repositories have a deb-src repository enabled. It's the equivilent of a half-tick.

You can find the repos without source with this command:

comm -3 \
    <(grep -Eo '^deb[^#]+' /etc/apt/sources.list{,.d/*.list} | sed 's/^[^ ]* //;s/#.*$//;s/ +$//' | sort -u) \
    <(grep -Eo '^deb-src[^#]+' /etc/apt/sources.list{,.d/*.list} | sed 's/^[^ ]* //;s/#.*$//;s/ +$//' | sort -u)