Linux · Filesystem Hierarchy (FHS)

Runtime PID and locking files for system services keep disappearing on reboot and you notice /var/run and /var/lock no longer hold them. Where did they move, and why do they not survive a reboot?

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More in Filesystem Hierarchy (FHS)

You move a script from an Ubuntu box to an obscure embedded distro and it can't find a binary at a hardcoded path. Why is assuming exact directory locations across Linux systems risky, and what standard is supposed to reduce that risk?

On a modern distribution you run ls -l /bin and see it points somewhere else instead of being a real directory of binaries. What happened to the historic /bin vs /usr/bin split?

What distinguishes the intended contents of /boot from those of /etc, and which one typically also stores the kernel?

After a reboot, entries under /dev look freshly rebuilt rather than persisted from last session. Why do device files behave this way, and what creates them?

Where does a modern distribution keep dynamically loadable kernel modules, and what has happened to /lib as a top-level directory?

You find stray numbered files sitting in /lost+found after an unclean shutdown. What put them there, and on which filesystems does this directory even exist?

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