Linux Important directories and files

1.1 Linux directory structuregeneral structure and characteristics of 1.1.1 directory

1. Everything starts with "root" and "/" is the starting point (vertex) of all directories.

2. The directory below the Linux root is a hierarchical tree structure.

3, resembles a tree hanging upside down.

1.1.2 relative path and absolute path difference

Relative path : The path of the path, relative to the current path, with no "/" Slash at the beginning of the path, such as etc.

Absolute path : the path from the root to the starting point, for example/ tmp

1.1.3/ down directories and their respective roles

├──bin Essential Command binaries the path to the necessary binary commands (all users)

├──boot Static files of the directory where the boot loader system boot program is located

├──dev Device files File

├──ETC host-specific System configuration, starting program

├──home General User Storage Directory

├──lib Essential GKFX Libraries and kernel modules shared libraries and kernel modules

├──mnt mount, point for mounting a filesystem temporarily temporary mount points

├──opt Additional Application Packages

├──proc Process and kernel information

├──root Super Admin Directory

├──sbin and management system-related commands (for administrators)

├──SRV service data provided by the system

├──tmp directory where temporary files are stored

├──usr (Unix software Resource) UNIX software resources

└──var Variable Data changes

1.2 Linux Important Files 1.2.1 nic configuration file

/etc/sysconfig/network-scripts/ifcfg-eth0

Example 1-1  

[Email protected] tmp]# Cat/etc/sysconfig/network-scripts/ifcfg-eth0

Device=eth0 #网卡设备的名字, Eth0 is the first piece, Eth1 is the second block.

Hwaddr=00:0c:29:06:16:2e #mac地址. The unique identity of the network card, clone virtual confidential deleted.

Type=ethernet #以太网.

Uuid=bdbcbab2-d91b-4d80-a3aa-841b9dd311b3 #网卡UUID. Clone virtual machines deleted.

Onboot=yes #开机时 whether the NIC and the system are started together.

Nm_controlled=no #网络管理器控制, do not accept.

Bootproto=none #启动协议, DHCP (Dynamic Host Configuration Protocol), static

ipaddr=10.0.0.7 #IP地址

netmask=255.255.255.0 #子网掩码

dns2=202.106.0.20 #第二个DNS.

gateway=10.0.0.2 #网关 (Internet access)

dns1=10.0.0.2 #第一个DNS.

Userctl=no

Peerdns=yes #要不要覆盖/etc/resolv.conf files (DNS client files)

Ipv6init=no #是否支持IPV6.

Setup Configuration Network is/etc/sysconfig/network-scripts/ifcfg-eth0

1.2.2 Linux system DNS Client configuration file

/etc/resolv.conf

Example 1-2  

DNS:www.oldboyedu.com---->1.1.1.1 "= = to convert the URL into an IP address,

[Email protected] tmp]# cat/etc/resolv.conf "= = view DNS

NameServer 10.0.0.2 "= = the first DNS

NameServer 202.106.0.20 "= = Second DNS

1.2.3 host name configuration file

/etc/sysconfig/network

(temporarily set host name):

[Email protected] tmp]# hostname oldgirl

[Email protected] tmp]# Logout

[[email protected] ~]# hostname changed

(permanent) Set host name:

[[Email protected] ~] #vim/etc/sysconfig/network

Networking=yes

Hostname=oldboy #主机名修改这里

Setup command to change.

1.2.4 Viewing host information:uname

Uname-n Viewing host names

Uname-r Viewing kernel information

Uname-m whether the view is 32-bit or 64-bit

UNAME-A Check all information.

Example 1-3  

[Email protected] ~]# uname-n

Oldgirl

[Email protected] ~]# uname-r

2.6.32-696.el6.x86_64

[Email protected] ~]# uname-m

x86_64

[Email protected] ~]# uname-a

Linux oldgirl 2.6.32-696.el6.x86_64 #1 SMP Tue Mar 19:29:05 UTC x86_64 x86_64 x86_64 gnu/linux

1.2.5 system local DNS parsing file

/etc/hosts Internal network To resolve the domain name of the tool, is to resolve the domain name to IP, commonly used for testing, server-to-site access

1.2.6 Configuring the boot automatically mount device files

/etc/fstab

Access the device to Linux, which is inaccessible by default (prison, no windows)

To access this device, it is necessary to mount (find an entrance to the device, press a door), the device's entrance is a directory,/mnt (the entrance of the temporary device).

Example 1-4  

Example: a manual mount procedure

[Email protected] ~]# ll/dev/cdrom "= = View the optical drive device.

lrwxrwxrwx. 1 root root 3 May 4 15:08/dev/cdrom-sr0

[Email protected] ~]# Cd/dev/cdrom "= = want to enter the optical drive device, but there is no entrance.

-BASH:CD:/dev/cdrom:not a directory

Mount:

[Email protected] ~]# mount/dev/cdrom/mnt "= = open a door for the optical drive device (/MNT),/mnt is called mount point.

Mount:block Device/dev/sr0 is write-protected, mounting read-only

[Email protected] ~]# ls/mnt

Centos_buildtag GPL Packages rpm-gpg-key-centos-6 rpm-gpg-key-centos-testing-6

EFI images release-notes-en-us.html rpm-gpg-key-centos-debug-6 TRANS. TBL

EULA Isolinux Repodata rpm-gpg-key-centos-security-6

1.2.7 storing files for boot program commands

/etc/rc.local

1.2.8 Setting the system run level profile

/etc/inittab

What is the runlevel?

0	Shutdown
1	Single User
2	Multi-user status without NFS
3	Text interface (multi-user state)
4	Reserved
5	Graphical interface
6	Restart

Linux Important directories and files