i always thought /usr stood for “user”. Please tell me I’m not the only one
Ken Thompson and Dennis Ritchie created Unix on a PDP-7 in 1969. Well around 1971 they upgraded to a PDP-11 with a pair of RK05 disk packs (1.5 megabytes each) for storage.
When the operating system grew too big to fit on the first RK05 disk pack (their root filesystem) they let it leak into the second one, which is where all the user home directories lived (which is why the mount was called /usr). They replicated all the OS directories under there (/bin, /sbin, /lib, /tmp…) and wrote files to those new directories because their original disk was out of space. When they got a third disk, they mounted it on /home and relocated all the user directories to there so the OS could consume all the space on both disks and grow to THREE WHOLE MEGABYTES. And thereafter /usr is used to store user programs while /home is used to store user data.
source: http://lists.busybox.net/pipermail/busybox/2010-December/074114.html
THREE WHOLE MEGABYTES
Me in 2024 holding a 4TB NVMe stick: Still not enough (it’s never enough)
I thought it was United System Resources.
And I still don’t know what’s the point in separating /bin, /sbin, /usr/bin and /usr/sbin.
Also /mnt and /media
Or why it’s /root and not /home/root
Mostly historical reasons, /home was often a network mounted directory, but /root must be local.
And only regular users have their home in /home
Idk why I feel compelled to add this info, but / doesn’t have to be local as long as the necessary kernel modules for mounting it are available in the initrd or built into the kernel.
/home is often on a separate volume. You’d want root to be available in a maintenance situation where /home may not be mounted.
I don’t recall the reasons for the addition but /media is newer than /mnt.
I don’t recall the reasons for the addition but /media is newer than /mnt.
Something to do with hard-coded mounts in /etc/fstab vs. dynamically-mounted removable media (USB drives etc.), I think.
And I still don’t know what’s the point in separating /bin, /sbin, /usr/bin and /usr/sbin.
This goes back to the olden days when disk space was measured in kilo and megabytes. /sbin/ and /usr/sbin have the files needed to start a bare bone Unix/Linux system, so that you could boot from a 800kb floppy and mount all other directories via network or other storage devices as needed.
Is there a reason to keep this structure other than „we’ve always been doing it like that“/backwards compatibility?
They hold “system binaries” meant for root user. It’s not a hard distinction but many if not most Linux fundamentals have their roots in very early computing, mainframes, Bell and Xerox, and this good idea has been carried into the here&now. Not sure about the provenance of this one, but it makes sense. isn’t /mnt /media different between distros? These aren’t hard and fast rules - some distros choose to keep files elsewhere from the “standard”.
/bin and /usr/bin, one is typically a symbolic link to another - they used to be stored on disks of different size, cost, and speed.
https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s16.html
https://unix.stackexchange.com/questions/5915/difference-between-bin-and-usr-bin
I think /mnt is where you manually mount a hard drive or other device if you’re just doing it temporarily, and /media has sub folders for stuff like cdrom drives or thumb drives?
Yeah, but why?
You can mount a hard drive anywhere, and why not put all the cdrom and thumbdrive folders in /mnt, too?
/sbin are system binaries, eg root only stuff, dunno the rest but I would guess there are some historical reasons for the bin usr/bin separation
I know the distinction between /bin and /sbin, I just don’t know what purpose it serves.
Historically, /bin contained binaries that were needed before /usr was mounted during the boot process (/usr was usually on a networked drive).
Nowadays that’s obsolete, and most distros go ahead and merge the directories.
I think it originally did under old Unix, it was what /home is nowadays; “Unix System Resources” is a backronym.
You are correct and this can be seen in some of the old AT&T demos from the '80s floating around on YouTube. There is even a chart that specifically labels a directory like /usr/bwk as the user’s home.
Plan 9 also uses this old convention; users live under /usr and there is no /home.
I was just about to post the same thing. I’ve been using Linux for almost 10 years. I never really understood the folder layout anyway into this detail. My reasoning always was that /lib was more system-wide and /usr/lib was for stuff installed for me only. That never made sense though, since there is only one /usr and not one for every user. But I never really thought further, I just let it be.
“Linux File Systems”
*List of root directories*
Uh, where are the file systems? EXT4… BTRFS… FAT32…
https://lemmy.world/post/9437525
My version of this with a bit more detail
Edit: Thank you, found it on your shared link ! 😄
Oh wow thank you ! Would it be to much to ask for a dark mode version? If there’s a one hit button to change into a more eye friendly color mode :)
Either way, thank your for sharing your work :))
I still have no clue where permanently attached USB SSDs are supposed to be mounted. I just shove them into LVM2 and put the mapper under /mnt since putting them under /home wouldn’t let other users access them.
permanently attached USB SSDs are supposed to be mounted
Just mount them somewhere under / device, so if a disk/mount fails the mounts depended on the path can´t also fail.
I keep my permanent mounts at /media/ and I have a udev rule, that all auto mounted media goes there, so /mnt stays empty. A funny case is that my projects BTRFS sub-volume also is mounted this way, although it is technically on the same device.
I don’t get why this sort of picture always gets posted and upvoted when it’s wrong for most distros nowadays.
Can you recommend one that is correct? I use pop_os (Ubuntu) and Arch. Kinda curious about either one
Not aware of any correct pictures, but I can tell you what’s wrong with this one
- /usr: explaining it as “Unix System Resources” is a bit vague
- /bin: /bin is usually a symlink to /usr/bin
- /sbin: /sbin is usually a symlink to /usr/sbin, distros like Fedora are also looking into merging sbin into bin
- /opt: many, I’d say most, “add-on applications” put themselves in bin
- /media: /media is usually a symlink to /run/media, also weird to mention CD-ROMs when flash drives and other forms of storage get mounted here by default
- /mnt: i would disagree about the temporary part, as I mentioned before, stuff like flash drives are usually mounted in /run/media by default
- /root: the root user is usually not enabled on home systems
- /lib: /lib is usually a symlink to /usr/lib
I would also like the mention that the FHS standard wasn’t designed to be elegant, well thought out system. It mainly documents how the filesystem has been traditionally laid out. I forget which folder(s), but once a new folder has been made just because the main hard drive in a developer’s system filled up so they created a new folder named something different on a secondary hard drive.
On my distro(Bazzite), /mnt is only a symlink to /var/mnt. Not sure why, but only found out the other day.
See file-hierarchy(7).
wait /usr doesn’t mean user?
/etc has to be the worst name in there
usr does mean user. It was the place for user managed stuff originally. The home directory used to be a sub directory of the usr directory.
The meaning and purpose of unix directories has very organically evolved. Heck, it’s still evolving. For example, the new .config directory in the home directory.
For example, the new .config directory in the home directory.
I hope slowly but surely no program will ever dump its config(s) as ~/.xyz.conf (or even worse in a program specific ~/.thisapp/;
The ~/.config/ scheme works as long as the programs don’t repeat the bad way of dumping files as ~/.config/thisconfig.txt. (I’m looking at you kde folks…) A unique dir in .config directory should be mandatory.
If I ever need to shed some cruft accumulated over the years in ~/.config/ this would make it a lot easier.
I don’t trust a graphic which explains /boot as “system boot loader files”…
According to this, it’s been around since the 70’s and was originally just a catch-all for files that didn’t fit in the other default directories, but over time has come to be mostly used for config files. I assume it would cause utter mayhem to try and change the name now so I guess it just sticks. Someone suggested “Edit To Configure” as a backronym to try and make it make more sense if that helps anyone lol.
Is there a historical reason?
If you’re asking that in anything Linux related, it’s probably a Yes 99% of the time LMAO
Not just Linux… 99% of the time you see something weird in the computing world, the reason is going to be “because history.”
