Kenneth, I wonder if you are making things too complicated for yourself. Also, please distinguish between "delete" and "uninstall". With uninstalling, the package manager handles the process (including deleting files). With deleting, the implication is that you are deleting the files, which is a poor way to remove programs, because the package manager does not know what is going on.

But I suspect that you already know that, as you use apt-get.

Now, to try to answer your questions, assuming that I have understood you correctly.

Quote Originally Posted by ken78724 View Post
… I am saving immense junk, caches, old/presumed to be deleted programs, crash reports, etc.
Linux has a lovely separation of areas (e.g. there is no Registry, as Windows has). All of your data is stored within your home folder, i.e. /home/ken (or whatever your user name is), a.k.a. ~, unless you have specifically placed your data elsewhere.

Furthermore, some of the folders that you mentioned are hidden folders — those beginning with a dot. In general, you will ignore those folders and back up only your normal, not-hidden folders, such as Documents, Pictures and Videos.

You may make exceptions for specific applications: for example, ~/.mozilla for Firefox settings (but you can exclude ~/.mozilla/firefox/*.default/Cache); ~/.thunderbird (again, exclude ~/.thunderbird/*.default/Cache).

Quote Originally Posted by ken78724 View Post
.. could [I] essentially delete major parts or all of the old programs, discarded programs, etc. using a terminal delete.
Well, whether you use a terminal or a GUI to uninstall makes no difference. In Ubuntu, you can use apt-get, Synaptic Package Manager, or Ubuntu Software Centre. Use whichever you prefer to install and uninstall; they work well together.

But bearing in mind what I mentioned about backing up your data, this should make no difference whatsoever to your backups! You should not be backing up anything outside your home folder, unless you had specific reason to place data elsewhere.

The Linux operating system is a small one, using little disk space compared to Windows, and on a modern computer you will not need to worry about uninstalling anything unless it causes a problem. However, if you are running short on space, you can use the following two commands, but they are unlikely to make much difference:
sudo apt-get autoremove
sudo apt-get clean
Those two commands can also be achieved through the GUI, though I do not remember how.

Quote Originally Posted by ken78724 View Post
I am paranoid regardless of how good back up may be that I'd lose the half million files, chapters, etc. that remain on my HD, to be edited and turned into manuscripts. … I am slow to learn how to copy those jewels to thumb drives, DVDs or a cloud storage.
Half a million? You have been busy! If you have not been backing up, you could lose everything at a stroke should your computer be stolen or the hard drive fail (hard drives do fail, sometimes suddenly without warning).

Sort out your backups now, before you do anything else!

Here is how I back up on a daily basis:

  • Cloud storage. I use SpiderOak, which is relatively cheap, highly reliable, totally secure, cross-platform, and easygoing with using it on multiple computers. Of course, you need broadband if you do this. I back up all essential data with this.

  • External USB hard drive. I use rdiff-backup, and save my entire home folder. This means that I have access to all hidden settings that I may later decide I wish I had kept.

Additionally, when I reinstall Linux:

  • I make a full backup of the entire Linux partitions onto the external USB hard drive using CloneZilla (you may prefer the more user-friendly RedoBackup). This means that if I totally screw up the installation, I can restore the entire drive back to where it was, and I have lost nothing. (BTW, this works brilliantly with Windows — saves you the hassle of reinstalling when viruses or BSOD plague you.)

Quote Originally Posted by ken78724 View Post
I want a general terminal deletion to remove ubuntu studio, multiple builds of mozilla firefox, sea monkey, opera and so forth.
All right, I don't know how you have managed to collect multiple builds of various programs. Have you not been using the package manager? If not, this is going to be a laborious, time-consuming and error-prone process.

On the other hand, if you have been using the package manager, you should always have only the latest version — the package manager replaces older versions with updated versions. That way, there is no need to worry about multiple builds. As I already stated, you also don't need to worry about uninstalling unused programs unless, for some reason, they cause a problem on your system.

If your hard drive is in a mess, there is only one way to clean it up. Back up as I have instructed (using cloud storage if you have the bandwidth, an external hard drive, and CloneZilla); then reinstall from scratch.

Quote Originally Posted by ken78724 View Post
… saving photos in Opera
I did not know that that was possible. I haven't used Opera except for browsing.

Quote Originally Posted by ken78724 View Post
… ended up with worthless crash reports that are in my cloud, on thumb drives and DVDs
My previous comments should have clarified things. I don't know where you have been saving your data, but your crash reports should not be anywhere that you would easily find them.

Ken, I hope that I have correctly understood what you have been asking. It sounds to me that, somehow, you made things terribly complicated for yourself. Linux should be easy; if you are struggling to do something, the chances are you should be doing it a different way.