Where does the ubuntu store the package dependency information

[princemaozh]

1) First trial:
At the beginning, my workstation is online, and I installed some packages using command "sudo apptitude install ...". (but I did NOT install vim-gnome)

Later my workstation becomes offline (without internet access), i typed the below command:



maoz@maoz-ws:~$ sudo aptitude install vim-gnome

and it says:


The following NEW packages will be installed:
libreadline5{a} libruby1.8{a} vim-gnome vim-gui-common{a} vim-runtime{a}
0 packages upgraded, 5 newly installed, 0 to remove and 350 not upgraded.
Need to get 8,716kB of archives. After unpacking 35.5MB will be used.
Do you want to continue? [Y/n/?]

the machine is offline and I did not install vim-gnome before. i am just wondering how aptitude knows the dependencies for vim-gnome?

2) second trial:
on an offline machine which is never online, i typed the same command:


maoz@maoz-ws2:~$ sudo aptitude install vim-gnome

but it says:


Couldn't find any package whose name or description matched "vim-gnome"
Couldn't find any package whose name or description matched "vim-gnome"
No packages will be installed, upgraded, or removed.
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B of archives. After unpacking 0B will be used.


So, why it behaves differently in these 2 cases? What is the trick?
Where (in which files) does the ubuntu store the package dependency information etc?

[dino99]

you can list them all for each package when using synaptic for example

[Toz]

So, why it behaves differently in these 2 cases? What is the trick?
Perhaps the apt cache was never updated on the second machine after install?

Where (in which files) does the ubuntu store the package dependency information etc?
You can use "apt-cache depends" and "apt-cache rdepends" to get dependency information. For example:

toz@oneiricX:/var/cache$ apt-cache policy vim-gnome
vim-gnome:
Installed: (none)
Candidate: 2:7.3.154+hg~74503f6ee649-2ubuntu3
Version table:
2:7.3.154+hg~74503f6ee649-2ubuntu3 0
500 http://ca.archive.ubuntu.com/ubuntu/ oneiric/main i386 Packages
toz@oneiricX:/var/cache$ apt-cache depends vim-gnome
vim-gnome
Depends: vim-gui-common
Depends: vim-common
Depends: vim-runtime
Depends: libacl1
Depends: libbonoboui2-0
Depends: libc6
Depends: libgdk-pixbuf2.0-0
Depends: libglib2.0-0
Depends: libgnome2-0
Depends: libgnomeui-0
Depends: libgpm2
Depends: libgtk2.0-0
Depends: libice6
Depends: liblua5.1-0
Depends: libpango1.0-0
Depends: libperl5.12
Depends: libpython2.7
Depends: libruby1.8
Depends: libselinux1
Depends: libsm6
Depends: libtinfo5
Depends: libx11-6
Depends: libxt6
Depends: tcl8.5
Suggests: cscope
Suggests: vim-doc
Suggests: ttf-dejavu
Suggests: gnome-icon-theme
toz@oneiricX:/var/cache$ apt-cache rdepends vim-gnome
vim-gnome
Reverse Depends:
|vimhelp-de
|vimhelp-de
vim-rails
gtimelog
|vim-runtime
|vim-gui-common
|vim-dbg
|vim-common

[princemaozh]

thanks for your reply, Toz.


Perhaps the apt cache was never updated on the second machine after install?

is there any way to update the apt cache on a offline machine?


You can use "apt-cache depends" and "apt-cache rdepends" to get dependency information. For example:

I want to know which file(s) actually store the package/dependency information... so that I can hack the file(s) on the offline machine. and therefore, the offline installation can proceed.

Anybody has ideas?

[Toz]

There are tools available that allow you to update offline machines. See: https://help.ubuntu.com/community/InstallingSoftware#Installing_packages_without_an_ Internet_connection