Red Hat LINUX 7.2 Reference Manual page 22

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The current FHS document is the authoritative reference to any FHS-compliant filesystem, but the
standard leaves many areas undefined or extensible. In this section, we provide an overview of the
standard and a description of the parts of the filesystem not covered by the standard.
The complete standard is available at:
http://www.pathname.com/fhs
Compliance with the standard means many things, but the two most important are compatibility with
other compliant systems and the ability to mount the /usr partition as read-only (because it contains
common executables and is not meant to be changed by users). Since /usr can be mounted read-only,
/usr can be mounted from the CD-ROM or from another machine via read-only NFS.
1.2.1 FHS Organization
The directories and files noted here are a small subset of those specified by the FHS document. Check
the latest FHS document for the most complete information.
The /dev Directory
The /dev directory contains filesystem entries which represent devices that are attached to the system.
These files are essential for the system to function properly.
The /etc Directory
The /etc directory is reserved for configuration files that are local to your machine. No binaries
are to be put in /etc. Any binaries that were formerly put in /etc should now go into /sbin or
possibly /bin.
The X11 and skel directories should be subdirectories of /etc:
/etc
|- X11
|- skel
The X11 directory is for X11 configuration files such as XF86Config. The skel directory is for
"skeleton" user files, which are used to populate a home directory when a user is first created.
The /lib Directory
The /lib directory should contain only those libraries that are needed to execute the binaries in /bin
and /sbin. These shared library images are particularly important for booting the system and exe-
cuting commands within the root filesystem.
The /mnt Directory
The /mnt directory refers to temporarily mounted filesystems, such as CD-ROMs and floppy disks.
Chapter 1:Filesystem Structure