Small screen size of ubuntu installation in VirtualBox

You must have mistyped the command (replaced a minus character by a space). Try again

sudo apt-get install virtualbox-ose-guest-dkms

Thanks for your kind help.

There is an error message:
E: Unable to locate package virtualbox-ose-guest-dkms

I havevirtualbox-dkms installed.
 The command uname -a in the virtualbox terminal gives:
4.2.0-27-generic 2016 i686 GNU/Linux

What OS is the guest and what OS is the host?

Thanks

The guest is Oracle VirtualBox and the host is Ubuntu 14.04.
Thanks for your help.

OK and what OS are you running in the guest OS?

Please provide the output of the commands

uname -a
lsb_release -crid
dpkg -l | grep virtualbox
dpkg --list 'virtualbox-guest*'

Thanks for the continued help.

The OS running in the guest OS is ubuntu-14.04.4-desktop-i386.

The required output is:

condy@condyHP:~$ uname -a
Linux condyHP 3.16.0-62-generic #83~14.04.1-Ubuntu SMP Fri Feb 26 22:52:39 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
condy@condyHP:~$ lsb_release -crid
Distributor ID: Ubuntu
Description: Ubuntu 14.04.4 LTS
Release: 14.04
Codename: trusty
condy@condyHP:~$ dpkg -l|grep virtualbox
ii unity-scope-virtualbox 0.1+13.10.20130723-0ubuntu1 all VirtualBox scope for Unity
ii virtualbox-5.0 5.0.14-105127~Ubuntu~trusty amd64 Oracle VM VirtualBox
condy@condyHP:~$ dpkg --list 'virtualbox-guest*'
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==============-============-============-=================================
un virtualbox-gue <none> <none> (no description available)

Thanks again and best wishes.

Wait, is Ubuntu the host system running Ubuntu as a VM? Just to clarify....

For the guest additions, I recommend that you download the file
http://download.virtualbox.org/virtualbox/5.0.14/Oracle_VM_VirtualBox_Extension_Pack-5.0.14-105127.vbox-extpack
and then open this file with virtualbox.

Then log in to the guest system and use the menu entry of the virtualbox window "Devices - Install Guest additions". This should lead to a pup-up in the guest system asking for confirmation to install the guest additions. When done eject the (virtual) guest additions cd from inside the guest system and restart the guest system.

The guest OS running is Ubuntu 14.04 as shown in the guest terminal output below:
condy@VirtualBox:~$ uname -a
Linux VirtualBox 4.2.0-27-generic #32~14.04.1-Ubuntu SMP Fri Jan 22 15:32:27 UTC 2016 i686 i686 i686 GNU/Linux
condy@VirtualBox:~$ lsb_release -crid
Distributor ID: Ubuntu
Description: Ubuntu 14.04.4 LTS
Release: 14.04
Codename: trusty

For the guest additions, I recommend that you download the file
http://download.virtualbox.org/virtualbox/5.0.14/Oracle_VM_VirtualBox_Extension_Pack-5.0.14-105127.vbox-extpack
and then open this file with virtualbox.

Then log in to the guest system and use the menu entry of the virtualbox window "Devices - Install Guest additions". This should lead to a pup-up in the guest system asking for confirmation to install the guest additions. When done eject the (virtual) guest additions cd from inside the guest system and restart the guest system.

Regarding the above instructions, please explain in simpler terms.

It's not an instruction. It's a question. Are you running Ubuntu as the OS installed on your PC, then running Ubuntu in Virtualbox?

Hi

Thank you both for your kind help and detailed instructions.
Yes, its Ubuntu as the OS installed on my PC, then Ubuntu running in Virtualbox.
I was confused about the part that required unmounting the CD device as I didn't have any in use. Then after a few trials it worked. The virtual box is now the same as the regular screen size.
Thanks, once again for the time and help.
Have a good day.

Thanks Manfred Hampl, that solved my question.