Understanding Linux directory structure

Understanding  Linux directory structure or file system structure

1./-ROOT:-

Every single file and directory starts from root directory .only root user has write privilege under this directory.it is like administrator account in windows operating systems./root is root user's home directory,not same as/.

2./bin-Users Binaries:-

Contains binary executable.common linux commands you need to use in single user mode are located under this directory. commands used by all the users of system are located here.

3./sbin – System Binaries:-

Just like /bin, /sbin also contains binary executables.But, the linux commands located under this directory are used typically by system aministrator, for system maintenance purpose.For example: iptables, reboot, fdisk, ifconfig, swapon

4./etc – Configuration Files:-

Contains configuration files required by all programs.This also contains startup and shutdown shell scripts used to start/stop individual programs.For example: /etc/resolv.conf, /etc/logrotate.conf

5./dev – Device Files:-

Contains device files.These include terminal devices, usb, or any device attached to the system.
For example: /dev/tty1, /dev/usbmon0.

6./proc – Process Information:-

Contains information about system process.This is a pseudo filesystem contains information about running process. For example: /proc/{pid} directory contains information about the process with that particular pid.This is a virtual filesystem with text information about system resources. For example: /proc/uptime

7./var – Variable Files:-

var stands for variable files.Content of the files that are expected to grow can be found under this directory.This includes — system log files (/var/log); packages and database files (/var/lib); emails (/var/mail); print queues (/var/spool); lock files (/var/lock); temp files needed across reboots (/var/tmp);

8./tmp – Temporary Files:-

Directory that contains temporary files created by system and users.Files under this directory are deleted when system is rebooted.

9./usr – User Programs:-

Contains binaries, libraries, documentation, and source-code for second level programs./usr/bin contains binary files for user programs. If you can’t find a user binary under /bin, look under /usr/bin. For example: at, awk, cc, less, scp./usr/sbin contains binary files for system administrators. If you can’t find a system binary under /sbin, look under /usr/sbin. For example: atd, cron, sshd, useradd, userdel
/usr/lib contains libraries for /usr/bin and /usr/sbin./usr/local contains users programs that you install from source. For example, when you install apache from source, it goes under /usr/local/apache2

10./home – Home Directories:-

Home directories for all users to store their personal files.For example: /home/john, /home/nikita

11./boot – Boot Loader Files:-

Contains boot loader related files.Kernel initrd, vmlinux, grub files are located under /boot.For example: initrd.img-2.6.32-24-generic, vmlinuz-2.6.32-24-generic

12./lib – System Libraries:-

Contains library files that supports the binaries located under /bin and /sbin.Library filenames are either ld* or lib*.so.*.For example: ld-2.11.1.so, libncurses.so.5.7

13./opt – Optional add-on Applications:-

opt stands for optional.Contains add-on applications from individual vendors.add-on applications should be installed under either /opt/ or /opt/ sub-directory.

14./mnt – Mount Directory:-

Temporary mount directory where sysadmins can mount filesystems.

15./media – Removable Media Devices:-

Temporary mount directory for removable devices.For examples, /media/cdrom for CD-ROM; /media/floppy for floppy drives; /media/cdrecorder for CD writer

16./srv – Service Data:-

srv stands for service.Contains server specific services related data.For example, /srv/cvs contains CVS related data.