Linux /Unix File Systems and Directories Command Line

Type of files used by Linux :

When working with Linux, you need to be aware of the fact that there are a number of different file types used by the file system. This is another area where the Linux file differ significantly from the widows file system. With a windows file system you basically have two different types in the file system.

Directories
Files

 

You can have normal file, hidden file, shortcut file, word processing file, executable file, etc.

However, these are a variety of different file type used by the system.

File type as shown below:

 

File Type

Description

Regular Files These files are like those used by the file systems of other operating system – e.g. Open Office.org files, executable files, images, text configuration files, etc.
Links These files are pointers that point to other files in the file system.
FIFOs FIFO stands for (First In First Out) these are special files used to move data from one running process on the system to another. A FIFO file is basically a queue where the first chunk of data added to the queue is the first chunk of the data removed from the queue. Data can only move in one direction through a FIFO.
Sockets Sockets are similar to FIFOs in that they are used to transfer information between sockets. With a socket, however, data can move bi-directionally.

Linux /Unix File Systems and Directories

Several major directories are associated with all modern Unix/Linux operating systems. These directories organize user files, drivers, kernels, logs, programs, utilities, and more into different categories. The standardization of the FHS makes it easier for user of other Unix-based operating systems to understand the basics of Linux. Every FHS start with the root directories, also known by its label, the single forward slash “/”. All the other directories shown in table are subdirectories of the root directory. Unless they are mounted separately, you can also find their files on the same partition as the root directory.

Command

Command Description

/ The root directory, the top level directory in the FHS. All other directories are sub directories of root, which is always mounted on same partition. All directories that are not mounted on a separate partition are include in the root directories partition.
/bin Essential command line utilities. Should not be mounted separately; otherwise, it could be difficult to get to these utilities when using a rescue disk.
/boot Includes Linux start up files, including the Linux Kernel. Can be small; 17MB usually adequate for a typical modular kernel. If you use multiple kernels, such as for testing a kernel upgrade, increase the size of this partition accordingly.
/etc Most basic configuration files.
/dev Hardware and software device drivers for everything from floppy drives to terminals. Do not mount this directory on separate partition.
/home Home directories are almost every user.
/lib Program library for the kernel and various command line utilities. Do not mount this directory on separate partition.
/mnt The mount point for the removable media including floppy drives, CD -ROM’s and zip disks.
/opt Application such as Wordperfect or Star Office.
/proc Currently running kernel-related process, including device assignment such as IRQ ports, I/O addresses, and DMA channels.
/root The home directory of the root user.
/sbin System administrator commands. Don’t mount this directory separately.
/tmp Temporary files. By default, Red Hat Linux deletes all files in this directory periodically.
/usr Small programs accessible to all user. Includes many system administrator commands and utilities.
/var Variable data, including log files and printer spools.

 

Some of the configuration files in  /etc directory that you should remember:

 

File

Function

/etc /fstab Lists the partition and file systems that will be automatically mounted when the system boots.
/etc /group Contains local group definitions.
/etc /grup.cong Contains configuration parameters for the GRUP boot loader (assuming its being used on the system).
/etc /hosts Contains a list of hostname-to-IP address mapping the system can use to resolve hostnames.
/etc /inittab Contains configuration parameter for the init process.
/etc /init.d/ A subdirectory that contains starup script for services install on the system. On Fedora or Red Hat system, these are located in /etc /rc.d /init.d.
/etc /modules.conf Contains configuration parameters for your kernel modules.
/etc /passwd Contains your system user account.
/etc /shadow Contains encrypted passwords for your user accounts.
/etc /X11/ Contains configuration files for X windows.

 

In this assignment I will instruct you about some basic commands of Linux. You will get seven virtual terminals when you perform fill installations. Although you can use graphics for daily task but here we are preparing for RHCE exam so you must use command line interface. Because all questions are based on command line in RHCE Exam.

 

-P. M. Sagavekar

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