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Samstag, 1. Februar 2014

WHAT´S WHAT IN THE LINUX DIRECTORY STRUCTURE? A INFOGUIDE

File Hierarchy Standard

While the Windows systems still retain characteristics such as the drive letter and the backward slash as a directory separator, the other operating systems such as Mac OS X and Linux, also root have long been approached and agreed on a common directory structure, starting from the root directory "/" called.
That there is such uniformity in terms of directory contents and descriptions, is the so-called Filesystem Hierarchy Standard, thanks to short FHS. This describes the development of a Unix directory system.The current version 2.3 is dated January 2004.
The FHS is interesting on the one hand for distribution developers , but it describes where the directories and files are found. On the other hand, the user benefits from this by quickly finds his way into other Linux and Unix variants without great incorporation .Order must be: The Filesystem Hierarchy Standard describes the structure of a Unix directory system.Order must be: The Filesystem Hierarchy Standard describes the structure of a Unix directory system.Nor is anything else important for the system administrator , however : there are no drive letters , partitions, hard disks and other storage media such as USB drives and DVD drives are easily integrated as a directory in the directory structure. The expert speaks of hanging or mounting.Theoretically can be hooked at any location directory. In practice, not that happens . For there are certain places that are provided of how the / tmp or / mnt . However, you can make when putting a server of this fact , by distributing the system on multiple disks or partitions. Anyone who hires sent , prevents , for example, an uncontrolled overflow of the physical memory or can quickly move the user data to another server in the event of a fall .----------Root (/)

Is the root , the root represented by the slash at the top of the whole UNIX directory system. What does the root file system must be sufficient to boot a Linux system or repair . These diagnostics , backup and restore utilities are also required, as configuration files and boot loader information . Important commands such as mount must therefore be directly accessible. But in the root directory typically is nothing except the directories , it is imperative that the appropriate subdirectories , including the programs are also present on the root partition.Very big the root file system has still not to be. On the contrary : It is advisable to keep this as small as possible in order to possibly run it from a USB stick can . In addition, a small root partition is less susceptible to damage , such as due to a system crash .--------------/bin

The / bin directory must be on the root partition. There are important Unix commands that can be executed by all users. These commands need to be executed if no other file system is mounted. In the / bin directory under other system commands for file permissions are (chgrp, chmod, chown), copy, create, move and delete directories and files for logging and mounting of file systems, the shell sh and the su program, with which you can change the user ID.
In /bin The archive also tools tar and cpio and gzip and gunzip programs pack. With this the administrator can recover a system if the root file system is intact. There is also the network statistics tool netstat and ping to test network connections. Should it be possible to repair a system on the network must also ftp or tfpt and its associated utilities available for an FTP connection.-------/ boot
 The directory must not be on the root partition. It contains the static files of the boot loader and all other necessary files to boot up. Here is also usually the system kernel, if it is not to be found in the root directory.-------- / dev
 Also, the / dev directory or its contents will be needed on the root partition. In this directory are character-oriented and block special files through which the access to devices such as hard drives and DVD drives or interfaces is controlled.-----/ etc

The / etc directory is as much on the root partition . After all there and in the underlying directories are the files for the system configuration. Some of the directories under / etc must be present on any Unix system , while others are optional . The configuration files for the X Window subsystem , so the graphics server , can be found in the / etc/X11 directory . There may also be the directory / etc / opt. There you will find in appropriate subdirectories , configuration files from the packages from the / opt directory .---------/ home

The / home directory hierarchy can be on anything other than the root partition. It contains the subdirectories the respective home directories of users. The names of the different home directories are identical to the user name. Your own home directory is the one to which a user has all access rights. Here he can create directories , delete files and store its own configuration data.
It makes sense to the / home hierarchy on its own partition, or even better: hard drive to create, and this for several reasons: there are no Benutzerquotas available, a user can bring the entire system to overflow. Another advantage of the physically separate / home hierarchy: one can relatively easily update a system and prevents the user directories then ON again. / lib, / lib32 and / lib64
 The / lib directory, in turn, must be on the root partition. This also applies for the corresponding 32 - or 64-bit libraries that are available in the respective subdirectories. Because these directories contain shared libraries and kernel modules, ie files with statements and definitions that are needed by multiple programs or loaded by the kernel. The libraries are needed to boot the system.-----------/ media
 Even / media belongs to the root partition. There, however, it takes hardly any space, because the directory is actually empty. It only serves as a mount for floppy disks (/ media / floppy), CD and DVD drives (/ media / cdrom / media / cdrecorder, / media / dvd) or Zip disks (/ media / zip). On systems with more than one same device can exist, which all end with a number of other directories (such as / media/cdrom0 and / media/cdrom1 for two CD drives), but even in such cases should continue to be the unqualified name (/ media / cdrom) remain. In some distributions there is also directly below the root directory mount points such as / cdrom. This does not correspond to the FHS. The reason given against such directories FHS authors argue that the same stood by mount points in the root of some more directories at the root level.-----/mnt

For the directory / mnt, the same applies as for / media: It should also be on the root partition. The list is as empty as / media and intended to temporarily mount a file system. This uses the administrator about this, make a backup or mirror disks. The bad habit, / mnt to use the directory for the mounting of drives, is in conflict with this Unix tradition.---/opt

The / opt directory is not needed for booting the system and can be outsourced to the / home directory to another partition. It serves to accommodate additional software packages which are not installed via the package manager. These are then available in the directory / opt / <package> / bin or / opt / <Provider>, manual pages for the programs are placed in / opt / <package> / share / man filed. Configuration files for these packages are stored in / etc / opt, variable data programs are usually in the directory / var / opt installed.----/ proc
 
The / proc directory is mentioned in the FHS only in the appendix. There is no standard Unix directory in Linux but it is the de facto standard for managing process and system information. Other derivatives make the example in the / dev / kmem. The / proc directory does not need to be on the root partition.--- / root 

The administrator not only has all rights, he also has his home directory is not in the same place as the ordinary user, but directly under / in the / root directory. The directory must not necessarily be present on the root partition. Then, make sure that it points to the root directory if it can not be located.-------/ sbinThis directory must exist on the root partition again . It contains programs for system administration . Even these, are still in the same directories / usr / sbin and / usr / local / sbin .Different: The specific features of Linux devote the authors of the FHS a separate chapter.Anders: The specific features of Linux devote the authors of the FHS a separate chapter.However sbin directory are / as opposed to the other two commands for booting , data recovery and restoration are required in addition to the commands in the / bin directory. Here , for example, are programs such as stop shutdown , fdisk to partition and fsck programs for checking the file systems. In the / usr/sbin- and / usr / local / sbin directories instead are programs that are used only after mounting the / usr directory.-----/ srvThe / srv directory must not be on the root partition. It contains data for services provided by the system, such as CGI scripts or data from a Web or FTP server. In most cases the data are sorted according to the protocol , ie www , ftp, rsync or cvs .---------/ tmpThe / tmp directory must not be included on the root partition. It is used for programs that generate the temporary files. Even users have write permission to this directory. Temporarily store files there but not makes sense , because the Posix standard recommends that data be deleted from the / tmp directory at the latest at every system startup . On some systems the / tmp directory is deleted regularly via cron job .----/ usrThe second largest area in the System directory is the / usr directory hierarchy. This area must not be on the root partition , because important system commands are either under / bin or under / sbin . In / usr , however, are available for each readable data ; Host-specific or other variable data is not stored here . In the / usr hierarchy , there are several directories that are required:In stand most user commands ,- are in header files for the C programming language,- contains libraries ,- contains the hierarchy of the local machine ( and is nitially after installation mostly empty) with the subdirectories and- does not contain quite as important utilities for the administrator to be used only after booting the system , and- in are architecture-independent data such as dictionaries , man pages or program documentations.------Depending on the configuration of the system , there are other sub-directories such as / usr/X11R6 with the X Window System , / usr / games with games and / usr / src with the source code. Also, on older systems, for compatibility reasons, various symbolic links on Unterzeichnisse of / var be present , such as / usr / spool as a link to the directory / var / spool . Reason for the shift : In the directory / usr is often accessed . However, it should not be fragmented by writing and deleting temporary data, since this would affect the throughput .----------/ var In / var, see files with variable data. Also, this directory must not on the root partition. Under / var are, for example, spool directories for mail users' mailboxes or print jobs, log files (eg, the file / var / log / messages with system messages) and also some other temporary files. All the data is written to the / var directory structure during operation, the previously found under / usr place. The directory hierarchy / var should be stored on a separate partition, just because in so many variable data are included. Who does not want or can, at least this part of the directory hierarchy should not harbor on the same partition as the root partition. Because it can quickly lead to an overflow of partition, for example, if the mail transport constantly producing errors and the log files full writes to the edge of the partition.----------Recommendations for a partition scheme To partition a Linux system, there are several possibilities. Most importantly, the root partition "/" must always physically contain / bin, / dev, / etc, / lib (/ lib32 and / lib64) and / sbin included. In Debian you go from about 150 to 250 MB of space for these directories. Ins / tmp directory users can write. It can use, among others, for images that are to be written to CD, DVD or Blu-ray. Some of these programs use the / tmp directory to temporarily storing therein data itself. Anyone who uses such burning programs should therefore schedule the space accordingly and reserve about 1 to 20 GB for the / tmp directory. Who does not use burning program that comes with much less space for the temporary directory. The Debian installation guide speaks in the case of 40 to 100 Mbytes of space.The / usr directory hierarchy is the part of the file system, which first requires the most space. According to the Debian installation instructions must be reserved for a generous workstation or server installation 4-6 GB. The / var directory hierarchy contains variable data. Here mails and software packages are cached, written log files and stored databases. In Debian the subdirectory / var / www is FHS-unkonform instead of / srv / www still used for Web pages. The size of / var strongly depends on the usage of the system. The space required can vary from 30 MB up to several GB.----------In / home mount the directories of the users . Accordingly, the size of the number of system users depends. According to the Debian installation instructions you should reserve at least 100 MB. Which these days is however rather ridiculous given the amount on MP3 files , photos and movies, store the user on the system. Here, the recommendation can only be : Make as much space available.Although it is generally made with a disk and a partition. But Cleverly is the use of at least two hard drives. A disk may contain the system , the other home directories . So you can quickly take over the / home directory hierarchy to another system . The home directories , you can also manage the Logical Volume Manager , It has the advantage that you can add more partitions of the directory tree if necessary easy.On the system disk again you should at least for / var, and / tmp define your own partitions - for / tmp , because all the write in the directory / var from the already mentioned reason : Does the partition becomes full , for example because the computer flooded with spam is , at least the rest of the system still responds . Tip: Anyone who has to worry about such a thing, and the directory / var / mail can swap on a separate partition .Another partition, you can provide for the swap space . Although the cache may simply lie in a file. Efficient However, it is this to treat a separate partition. It divided in their opinions as to whether the should be on the system board or elsewhere: Some are of the view swap space and the system should be on different SCSI or IDE channels . As a size recommendation is available in Linux circles, the Pi -by- Rule of thumb : The swap partition should be as large as the RAM .---------Current project UsrMove Many well-known distributions such as Fedora 17 have currently to some directories. This is to / bin, / sbin, / lib and / lib64, which migrate to the directory / usr. It was suggested this cleanup the directory structure of the developers of Fedora distributions like Gentoo and openSUSE (suggested for version 12.2) will follow. The initiative, known as UsrMove the root tree is to act tidier, the sharing of / bin and / usr / bin is also more confusing than useful. The compatibility with the existing structure is still maintained by symbolic links. When and if the modified directory structure flows into the FHS standard, is currently unknown. (MJE / cvi / tecChannel)-------------------SO THATS ALL,I HOPE IT HELPS A LIL BIT!!!I WISH A NICE DAY AND MANY GREEEEETZ!!!-CALIBAN666- 2014------------------


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