It depends. I’ve done it a few different ways:

• YOLO: especially with thugs like PHP you only affect one page at a time and with low traffic the odds of a problem is small
• Maintenance page: temporarily show a page. Some servers like IIS have this built in. Otherwise it’s a simple update to httpd conf
• In a cluster environment, just take the node you’re updating out of rotation, and only update one node at a time.
• Copy and switch like you suggested. Can be combined with any of the above and is a smart move if upload is slow or can be interrupted, or it’s cumbersome to restore the old files

Edit: spelling

Since unity is c# I think maybe you phrased that opposite of what you meant?

Anyway, I work in an enterprise environment. We use both Java and .Net, and it largely depends on which group you’re in. Neither Java nor .Net is going away anytime soon.

You really don’t get to stick with just one thing in a developer career. Learn a little of everything, especially multiple paradigms, and specialize in a few related to the business you work for.

A key skill is adaptability, learning as you go. If you make yourself too specialized, you’ll set yourself up for being laid off when your skills become obsolete. I have interviewed a few older IT people in that situation, only a few years from retirement.

• Commodore 64 (kernal)
• Amiga OS
• MS-DOS 3.2, 5.0
• Windows 3.1
• Slackware Linux
• Windows NT 4
• RedHat Linux
• Windows XP
• Ubuntu Linux
• Windows 7
• Windows 10
• Rasbian
• PopOS

Roughly in order of appearance. Personal devices only. I used many more for work.

What about volunteering? Usually no credentials or experience is required. You get out of the house, get to be around people, and you get the satisfaction of feeling like you are doing something useful, which is rewarding in itself.

It could be anything. You have all kinds of organizations wanting volunteer help: social outreach programs, churches, scouts, clubs, etc. See if anything local catches your interest.

To manage packages on the terminal, I personally like to use aptitude which has a nice visual interface to find, install, and remove packages. It also lets you resolve conflicts interactively. If you do not want a separate tool, you can use apt-cache search to search for new packages.

As is typical with Linux, there are multiple ways to do it. I found an article that outlines a few alternatives.

My car’s extended warranty.

This is the answer. Here in this US checks are still widely used, and sometimes, thanks to processing fees, the only payment except cash someone will accept. Mobile payments, though available, haven’t really taken off here like in Europe.

You haven’t lived until you’ve installed Slackware from floppy disks and compiled the necessary network drivers into the kernel by hand. Good times, but never again.