Difference between /bin, /sbin, /usr/bin, /usr/sbin

[Hektor]

What is the difference between the directories /bin, /sbin, /usr/bin, /usr/sbin? Why can't they all just be in one directory - /bin?

[Jordan]

If you do a "man hier" you can see a "description of the file system hierarchy". It shows what different directories are for:

       /bin   This directory contains executable programs which are needed  in
              single user mode and to bring the system up or repair it.

       /sbin  Like /bin, this directory holds commands needed to boot the sys-
              tem, but which are usually not executed by normal users.

       /usr/bin
              This  is  the  primary  directory for executable programs.  Most
              programs executed by normal users which are not needed for boot-
              ing  or  for  repairing  the  system and which are not installed
              locally should be placed in this directory.

       /usr/sbin
              This  directory contains program binaries for system administra-
              tion which are not essential for the boot process, for  mounting
              /usr, or for system repair.

[mop]

Interesting to learn. I have never heard of a man hier.

[TcM]

What's a man hier? Is that a command in Linux?

[Jordan]

It is the manual page for the Linux file system hierarchy. Just about every command has a manual page which can be seen using "man <command" such as "man vi".

[TcM]

So it's like a help file, right?

[Tor]

Yes, they are basically help files. If you bought the software in a box it would be the hard-paper "manual" that came with the software.