Cfrtjryk

Is there any possibility to use a different directory than /usr as the standard directory to install things? I am asking, since I got an Endless OS system where /usr is read-only, thus not being able to do things the "standard" way.

In other words: Is there a way to create another folder, say in my home directory (let's call it "user"), and "share" all commands and dependencies between /usr and /home/user? So, for example, when I want to install perl-tk in the /home/user - directory, I can make use of the perl packages already installed in the /usr/whatever folder during make install?

I cannot change /usr (there is a way with an overlay, however by system update, these changes are gone), so I need to somehow "work outside" it, but somehow "link" to it still.

Changing system would be an obvious option, but also just eluding the challenge ;)

It may be that Endless OS is not the right tool to be able to accomplish what you want. From the Endless OS Developer page,

Endless OS

Not your typical Linux distribution. We don’t use rpm, apt, or any other packaging system. We use a read-only root file system managed by OSTree with application bundles overlaid on top. We have a different target user. Most desktop Linux distributions are oriented towards tech-savvy users and developers.
Simplicity is the key, so we carefully pick and choose the best applications available for our users.
A number of core technologies underlie our OS, in particular the Linux kernel, OSTree, systemd, GNU, X, GNOME, and Xapian.

Yes, it is possible to install software to directories other than /usr.

One example (system-wide) is /usr/local. (Which might still not help you directly, since your /usr is read-only.) The /usr/local directory matches /usr in its layout (it has a /bin, /lib etc.) In most cases, it is used to distinguish packages shipped as part of your base OS (which will go into /usr) from those installed from source by the systemd administrator (which will go into /usr/local.)

There is also /opt which is meant to install packages into separate per-package directories. So, for instance, you could install Perl 6 there under /opt/perl6 and that would only contain Perl and nothing else. You would keep separate directories for the separate packages, which usually makes it easy to "uninstall" a package by just removing its directory. You usually need to set $PATH appropriately to access the programs installed there, or create symlinks in some other bin directory that's already in $PATH to access those. Management of /opt is usually meant for the administrator, and considering you need to update $PATH for every package you install, it might not be the best option...

For installing software under your $HOME directory, one possible approach is to create a .local subdirectory at the top of it and match the /usr or /usr/local hierarchy.

So maybe try this:

mkdir ~/.local

And then use it as --prefix when you're installing a new package. For instance, if the package uses an autoconf-style configure script, you can build and install it using:

./configure --prefix="$HOME/.local"

make

make install

You need to add ~/.local to your $PATH so you can access programs there. So do that in your ~/.bashrc:

PATH=$HOME/.local:$PATH

export PATH

Open a new shell (new terminal, or log out and log in again) for the change to take effect. Or just run that same command on your existing shell. You should be able to execute the programs from ~/.local/bin direcly now.

I hope this helps answer your question, or at least points you in the right direction!