a handy one to remember - following do not need sudo - is
just add the package name, so, this in two of my stable
Code:
chris@TriciaCinn-SSD:~$ apt-cache policy libc6
libc6:
Installed: 2.27-3ubuntu1
Candidate: 2.27-3ubuntu1
Version table:
*** 2.27-3ubuntu1 500
500 http://mirror.aarnet.edu.au/pub/ubuntu/archive bionic/main amd64 Packages
100 /var/lib/dpkg/status
applies to you, charlie, and to buddha
Code:
chris@eoan-ermine-mate-ssd:~$ apt-cache policy libc6
libc6:
Installed: 2.30-0ubuntu2.1
Candidate: 2.30-0ubuntu2.1
Version table:
*** 2.30-0ubuntu2.1 500
500 http://archive.ubuntu.nautile.nc/ubuntu eoan-updates/main amd64 Packages
100 /var/lib/dpkg/status
2.30-0ubuntu2 500
500 http://archive.ubuntu.nautile.nc/ubuntu eoan/main amd64 Packages
... so buddha's ubuntu 19.10 can take the v6 of virtualbox, and charlie's can't.
if there was an update outstanding, you would see it in the difference between "installed:" and "candidate:"
of course we can go to a website such as pkgs.org and get a newer package, but unless you know what you are doing and do your homework, you may take a journey across the River Styx and enter
... drumroll
DEPENDENCY HELL
there are various ways of determining what depends on what, but one i like that is in our repos is
apt-rdepends
Code:
sudo apt-get -y install apt-rdepends
once installed, i can type, enter and get the following from charlie's mint, similarly with buddha's ubuntu
Code:
chris@TriciaCinn-SSD:~$ apt-rdepends libc6
Reading package lists... Done
Building dependency tree
Reading state information... Done
libc6
Depends: libgcc1
libgcc1
Depends: gcc-8-base (= 8.4.0-1ubuntu1~18.04)
Depends: libc6 (>= 2.14)
gcc-8-base
... so libc6 needs to have libgcc1 installed, which in turn relies on gcc-8-base, AND a version of libc6 greater than or equal to v2.14
and libc6 also depends on having that gcc-8-base too
confused?
good
- this is just dipping your toes into dependency hell.
the apt-rdepends command acted recursively in the above case.
we can turn that around with the following, and get it to tell us
what depends on libc6.
type and enter the following and then hold on to your hat
gone goggle-eyed?
i knew in advance that there would be a lot of output, so i entered
Code:
apt-rdepends -r libc6 > depends-on-libc6.txt
which generates a text file of that name.
going to my Nemo file manager, i open the file, which is a whopping 12.4 MB, and has
265,317 lines in it.
so libc6 has 265,000+ packages depending on it - i seriously would not muck with it, hence i have to disagree with my Green Hornet friend.
more to follow after coffee