Lesson 4 directory Structure

4.1 Directory structure Features

1, all the directory of Linux is a hierarchical, inverted tree-like structure , all directories start with the root directory "/".

2. different directory data can span different disk partitions and different disk devices

3. all catalogs are organized and named according to certain categories

4, the Linux system default device is not accessible, must be hung in the existing directory structure system.

5, Mount is to give the device a access to the entrance, which is called the mount point . The mount point must be an absolute path.

6. Mount disk device: Mount; unmount disk device: Umount

7, through the df-h command can view the disk partition situation

[Email protected] ~]# df-h

Filesystem Size used Avail use% mounted on

/dev/sda3 6.9G 1.5G 5.1G 23%/

Tmpfs 238M 0 238M 0%/dev/shm

/DEV/SDA1 190M 36M 145M 20%/boot

8. The partition of the system is automatically mounted via/etc/fstab file boot.

4.2 The meaning of the first level directory

Directory	File contents to be placed
/	root directory, all directory structures of the Linux file system start from the root directory
/bin	Binary commands that can be executed in single-user mode for all users
/sbin	Binary commands that can only be executed by super Administrator root
/boot	directory where the boot loader is installed
/dev	directory where device files are stored
/etc	System configuration files and service profiles
/home	Home directory for ordinary users
/lib	Directories in which shared libraries and kernel modules reside
/lost+found	When the system suddenly shuts down or crashes, files that have not yet been saved will be placed in this directory. The fsck command restores the data during boot and the data that cannot be recovered is deleted.

/mnt	Mount directory that mounts temporary storage devices
/opt	installation directory for third-party software
/proc	Virtual file system for kernel and process store information
/selinux	Location of SELinux file storage
/srv	Site-specific data, provided by the system
/sys	Real-time information about the system kernel and drivers
/tmp	Temporary files. Data is not retained during system restart
/ usr	A file or directory related to a system user, such as an application and associated library files. /usr/local placing user-installed programs
/var	During the normal operation of the system, the contents of the file are constantly changing.

4.3/etc Sub-directory meaning

Directory	The contents of the file to be placed
/etc/sysconfig/network-scripts/ifcfg-eth0	NIC configuration file
/etc/resolv.conf	DNS Client configuration file
/etc/hosts	Local domain name resolution file, equivalent to DNS
/etc/sysconfig/network	Gateway and Host name configuration
/etc/fstab	Automatically mount files on boot, all disk partitions will be automatically mounted on boot
/etc/inittab	System initialization configuration file
/etc/issue	Default output kernel version information
/etc/skel/	When you create a normal user account, the directory is copied to your home directory
/etc/sudoers	Configuration files related to the sudo command

/etc/profile	Global environment variable configuration file
/etc/bashrc	Global environment variable configuration file
/etc/syslog.conf	System Log Parameter Configuration

4.4/USR Directory

Directory	Configuration files that should be placed
/usr/bin	Non-essential executable file for all users
/usr/sbin	System commands required for non-system uptime
/usr/lib	Libraries for binary files in/usr/bin and/usr/sbin
/usr/local	Place the user's local Setup program

4.5/var Directory

Directory	Configuration files that should be placed
/var/log/mesages	System log information, poll by week
/var/log/secure	system security log that logs information about the login system. Whether the login succeeds or the login fails, it will be recorded.
/var/spool/cron/root	Timer configuration file Directory
/var/spool/clientmqueue	When the mail service is not turned on, all messages sent to the mail administrator are placed here
/var/spool/mail	Mail directory

4.6/proc Directory

Directory	Configuration files that should be placed
/proc/meminfo	Memory information
/proc/cpuinfo	View CPU Information
/proc/loadavg	Viewing average load information
/proc/mounts	Mount the information in detail when with df-h

4.7/dev Directory

Directory	Configuration files that should be placed
/dev/zero	Unlimited ASCII 0
/dev/null	Data black hole
/dev/cdrom	Connection file, connecting to/dev/sr0

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Lesson 4 directory Structure