Understanding the bin, sbin, usr/bin, usr/sbin split (2010)

4 months ago

The split between /bin, /sbin, /usr/bin, and /usr/sbin originated from Unix's early days when disk space was limited.
Initially, /usr was used to extend the root filesystem when the primary disk ran out of space.
Rules were created to manage dependencies during system boot, such as keeping essential commands like 'mount' outside /usr.
Modern systems use initrd or initramfs to handle early boot dependencies, making the original split obsolete.
Shared libraries introduced dependency issues between /lib and /usr/bin, complicating the split further.
Hard drive advancements in the 1990s rendered the space-saving rationale irrelevant.
Additional directories like /usr/local and /opt were introduced for site-specific and third-party software, adding complexity.
Different distributions have inconsistent rules for directories like /tmp and /var/tmp.
Standards bodies have perpetuated the split without understanding its historical context.
BusyBox follows traditional placement for compatibility, though the split lacks practical justification today.

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