FHS-3.0 describes it as:

Shareable, readonly data. That means that /usr should be shareable between various FHS-compliant hosts and must not be written to.

I am a bit confused by what this means. Does this means that the binaries or whatever other files inside should be copy-pasteable onto another machine, and have them function perfectly fine?

1 Answer 1


I think what it means is only that distros shouldn't assume that an installation has sole ownership of /usr, not that everything in /usr is expected to work with all FHS-compliant systems. I think I have heard of /usr being served over the network (via NFS for example) for a bunch of systems running the same distro. Since /usr is where the bulk of all installed files reside, this makes for a lot of space savings. Also, I think it's not unusual to have /usr a separate filesystem in any case, mounted read-only for additional security, so the "must not be written to" part helps with that as well.

/etc can't be shared in this manner - some files, like /etc/hostname are necessarily different for each host (though most files in /etc can be so shared, I think). Nor can /var - it wouldn't make sense to have two services on different systems logging to the same file, for example.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .