How to obtain list of installed packages

[Bret Busby]

On 12/05/2016, Colin Law <clanlaw at gmail.com> wrote:
> On 10 May 2016 at 19:16, Bret Busby <bret.busby at gmail.com> wrote:
>> Hello.
>>
>> I believe that this question gets asked from time to time, but I do
>> not know that a solution has been found.
>>
>> The question is this; does a utility exist, that can be ran, to
>> produce a list of installed packages, in a way that can be used by a
>> user (system administrator), to perform a system rebuild, so as to,
>> after installing the system again, ensure that all of the optional
>> packages that were previously installed, are again installed in the
>> new system installation?
>>
>> I am running UbuntuMate 15.10, on a system with other Linux operating
>> system versions (which are inappropriate for the hardware), that are
>> not used, installed, and, with wanting to eliminate them, and,
>> repartition the HDD, for a number of reasons, including occasionally
>> seeing an error message that states that the partitioning is out of
>> alignment, or something (I am not sure of the exact message, or, how
>> to reproduce the error message), I believe that a new installation of
>> the operating system, is needed, but, I want to again, have all of the
>> existing installed optional packages, installed and operable.
>
> You could use gparted to remove unwanted partitions and resize the one
> you want to keep (booting off a live image).  You might then have to
> re-install grub to stop it being confused by the missing partitions.
> Much less work than re-installing.  Obviously have everything backed
> up first in case it goes horribly wrong.
>
> Colin

Hello.

Thank you for the advice.

However, whilst it is a while ( a few weeks or so), since I last saw
the error message about the problems with the partitioning, and, I do
not know how to get the error message again, to be able to write it
down, word for word, to explicitly and accurately reproduce the exact
message, from memory, it is something along the lines of "Your hard
drive partitioning is stuffed - the partition sizes and (/or) the
start and end points of the partitions do not match the partition
table", and, from memory, it involved the equivalent (as it no longer
exists, with the GPT, rather than a FAT, or so I understand) of an
extended partition, where, if this was an older FAT system, and I had
created an extended partition in which to set up the partitions to
install the various operating systems other than the pre-installed
Windows, the whole of the extended partition would need to be deleted
and created again, so that the start and end points of the extended
partition, and each of the logical partitions within it, could be
(reasonably) ensured to be correctly placed.

The error that I got, is something that I had not previously
encountered; either the error itself, or, the type of error, which, to
me, with my (relative) lack of knowledge in this area, is the
equivalent of the error message stating that a File Allocation Table
is wrong/stuffed/needing replacement.

Thus, I was intending to, or, investigating/considering repartitioning
the whole of the HDD, as much as possible (including eliminating the
infidel MS Windows 8, which I could never use without great anguish,
and, for which, I have forgotten the passwords), and, creating a new
system of partitions, with a single installed operating system (which,
at this stage, would be reinstalled UnbuntuMATE 15.10, as I have seen
on the list, many reports of problems with Ubuntu 16.04), which I
know, has drivers for all of the hardware of the computer, and, which
is the only operating system (other than MS Windows 8, and possibly
later versions) that I know to have all of the drivers for the
hardware and thence, be (relatively) fully functional on the computer.

Since posting my original query, in this thread, it has occurred to
me, that, when I have the available time, the simplest way to achieve
what I want, regarding the list of packages, is to work through the
Applications menu, and write down every application name for each
category of applications, and then, to ensure that each of those
applications listed, is installed in the new build.

>From the responses that I have seen posted on the list, so far, I am
not aware of a simpler or more efficient method of obtaining a list of
the packages that I need to install, in addition to the base system
packages, in order to replicate, as much as possible, the
functionality of the existing system.

However, with the perceived expectation of the time required to do
that, it would have to wait, due to other issues with which I have to
deal.

-- 

Bret Busby
Armadale
West Australia

..............

"So once you do know what the question actually is,
 you'll know what the answer means."
- Deep Thought,
 Chapter 28 of Book 1 of
 "The Hitchhiker's Guide to the Galaxy:
 A Trilogy In Four Parts",
 written by Douglas Adams,
 published by Pan Books, 1992

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