Why Do Arch Linux Pacman Packages Have 3 File Extensions

What are some ways I can install .rpm files in Linux?

It depends on your distribution. The usual method that is common to all RPM-based distributions is:# rpm -i FILE
where FILE is the name of your rpm file, including the `.rpm` file extension and # denotes that this should be run as root. This does not install any missing dependencies, however, so if there are missing dependencies this command will fail. The better way to install the package is to use your distribution’s front-end for the rpm package manager like DNF for Fedora, urpmi for Mandriva derivatives, yum for CentOS and its derivatives and ZYpp for openSUSE. For example, if you’re running Fedora you’d use:# dnf install FILE
to install the rpm package. With urpmi it is:# urpmi FILE
with yum it is:# yum install FILE
while with ZYpp it is:# zypper install FILE
If you’re using a distribution that does not use the RPM package manager or its front-ends you’d have two options.Firstly, you can decompress the rpm package (e.g. using bsdtar xf FILE) and move its contents to where they belong in your root file system. This should work, if you’ve met the dependencies of the package, but it’s a dangerous method as it might overwrite files installed by your package manager. Likewise if you install a package that shares some of the rpm package’s file it will overwrite the contents of your rpm file.Secondly, you can construct a package for your distribution’s package manager that uses the contents from the rpm file and install said package using your package manager. Like I use Arch Linux and on Arch Linux I can write a PKGBUILD (used to build packages for Arch Linux) that will extract the rpm and move its contents to where they belong on my filesystem. Then I would run makepkg in the directory in which the PKGBUILD was found and then install the resulting .pkg.tar.xz file created by makepkg using pacman with sudo pacman -U FILE, where PACKAGE is the name of said file (including the .pkg.tar.xz file extension).

What are some "Arch Linux-like" replacements for APT and APT-GET in Debian?

Each major Linux branch has its own package manager. In Debian and its derivatives it’s generally APT (Advances Packaging Tool) and works on DEB files containing the package configurations and executables, possibly with GUI tools on top of it like Synaptic / Aptitude. Actually APT is the tool used in the underlying DPKG package manager which operates on DEB files.In Fedora / RedHat it’s generally in RPM files and you use YUM (Yellow Dog Updater - Modified), since Fedora 18 it’s been extended to the DNF (Dandified YUM) and become the standard since version 22. In fact both YUM and DNF are tools to operate on the underlying RPM manager - much the same as APT works on top of DPKG.Both DEB/RPM files are simply archive format files (something like a ZIP file) with standard contents as a sort of description for what is inside, what is needed as dependencies, and where to install the content. Also likely to have stuff like setup instructions included - e.g. what to add to the startup scripts to run the program once installed.Similar in things like openSUSE you get ZypperArch has its own called PacMan. This generally operates on tar.xz files. These are exactly like ZIP files, just using tar to combine the content into one file and the XZ to compress them. Though PacMan also expects the content in a standard format with specific files inside to state the requirements of how to install.Arch also includes a from-source install tool in ABS (Arch Build System). The others don’t have something specifically designed just to do this, though they have means of configuring source code compilers to generate DEB/RPM packages through the general purpose make command.Other Linuxes have similar ideas. E.g. Gentoo tends to only be from source code. Its major tool for this is ebuild and emerge. It also has a more similar tool to APT called Portage Package Manager.For very light weight Linuxes there are tools like ipkg (or the derivative opkg / qpkg) - usually used in stuff like OpenWRT which is the sort of Linux installed inside a router.There are even 3rd party stuff like ZeroInstall (0install) which works on many Linuxes as a cross-platform package manager. E.g. it’s designed for all of Arch, Debian, Knoppix, Mint, Ubuntu, Fedora, Gentoo, OpenSUSE, RedHat & Slackware.You also may want to look at some alternatives and user comments about each: Slant - 15 best Linux package managers as of 2017. Or for some actual comparisons: A Comparison of Popular Linux Package Managers

Why shouldn't I install a .deb file on an Arch-based system?

If you are using arch linux in its pure form, it uses pacman as package manager, and you won't be able to install .deb files.If you know tinkering your arch installation a bit, there are plenty of ways in which you could make use of precompiled .deb packages (of same architecture). For that matter, many aur packages are using .deb files as source. Eg: AUR (en) - google-chromeIn arch almost all trickeries in the area of package management are viable. It's even possible to install dpkg inside arch. I would advice you to read some good PKGBUILD files utilizing .deb packages.So, basically there are no restrictions on using .deb files. But whenever arch official / aur packages are available they are the best options.

As a 3 month Linux user that already made Arch Linux run successfully, should I try Gentoo or stay in Arch (for daily use)?

Definitely move to Gentoo. If you can install Arch succesfully you should have no problem with Gentoo. There’s a popular myth that compiling takes too long and causes too much trouble to be worthwhile, but once you’ve optimized Portage, and on a modern system, it doesn’t take long at all, except for a very few select packages. Compared the trauma of installing from a bare disk, it isn’t much of a leap. To compare, the updates are still faster than Windows 10, even though their updates are binaries. When you first install, compiling is going to take a few hours, but after that it’s a fairly simple job.The Portage package manager makes compiling very straightforward, and allows you to customize the software you install, in terms of adding or removing features, and allows you to build binary packages for other systems and build bespoke packages for software that isn’t currently supported. The count of packages looks low compared to other distros, but it’s important to remember that there’s no need to have duplicate packages for different hardware (e.g.32 and 64 bit versions), and in many cases, what would be an add-on package elsewhere, can be handled by setting a use flag in Portage.The software you build has been compiled specifically for your hardware, and I’ve found that this makes a very stable and fast system. Binary distributions, on ther other hand, have packages that have to work on a variety of systems, which increases the risk of compatibility problems and bloat (which is still fairly low).I wouldn’t, and didn’t bother with a virtual machine for Gentoo; I installed it on a different hard disk, and once I was satisfied it was a contender I migrated it to my SSD (easily done).

Which one would you prefer, Ubuntu or Arch Linux?

I use Arch Linux, Debian (jessie) (on my laptop) and Ubuntu 14.04 (on my desktop). I am a fan of the Arch Way. The best thing about Arch is undoubtedly the ArchWiki. The best thing about Ubuntu is undoubtedly Debian's Advanced Packaging Tool and Personal Package Archives.Ultimately, you can have an Arch Linux system that looks and works exactly like an Ubuntu system, and vice versa (except for rare exceptions like systemd, but systemd is coming to Ubuntu). You can use Ubuntu's alternate install image (which has not yet been released for main Ubuntu but is available for Lubuntu) to build your system package by package if you want to, (which is what most Arch Linux users do anyway). Except for core system tasks like package installation, all three of my systems are functionally the same. (Even for package installation, for software in the main repos, it is practically the same.)While Arch lets you on the bleeding edge of practically anything in the main repositories and most things in the AUR, there are PPAs for a lot of major projects which you can use to stay on the bleeding edge on Ubuntu. Even more than Arch, if you use nightly PPAs.Fundamentally, there's no reason to prefer Arch over Ubuntu or Ubuntu over Arch, or Debian over the others or the others over Debian. You can mold one in the other's image if you want to.One thing I will say: Once you do build your system package by package, configuration file by configuration file, whether it be by Ubuntu alternate, Debian netinstall or Arch Linux, if you are open minded enough to see that others' needs are not necessarily like your own, you'll appreciate the effort that Ubuntu developers put into making it easy to use, sometimes in spite of upstream efforts.

Which Linux distribution is the best for a programmer?

I’d suggest the important things are which desktop/UI you want to use, and then decide which Linux distribution that has that desktop/UI has the easiest installation and management. Personally I use Debian Sid and Fedora Rawhide with GNOME. Many people hate GNOME for some reason, I find it great. There are though many UIs for Linux, GNOME, Unity, Cinnamon, Mate, KDE, XFCE, LXDE, to name a few. They all have their adherents and naysayers, the only way to know is to try them all before choosing – which is clearly impossible. Debian, Ubuntu, Mint, Fedora, and Arch are arguably the distributions with the largest user base and hence support base. Ubuntu and Fedora have the advantage of being the bases for commercial operations and so they get a lot of commercial input. If push came to shove I would suggest Fedora 25, 26 soon to appear. It starts with GNOME but you can easily switch to LXDE which is probably the best lightweight desktop/UI.The important thing is that they all support Python very well indeed. And remember this means Python 3. All the distros support Wine, but as others have said you will not need this for Python activity, so I assume that is a question with a different goal in mind. Games perhaps.Of course all this is missing that there is a platform independent Python distribution called Anaconda (or Miniconda for those wanting the stripped down version) managed by Continuum Analytics. This means you can use all the same Python stuff on Linux, macOS, and Windows. Using this makes the platform Python system redundant. This is the choice for most data science and AI folk.