Linux Learning Notes

Linux Application watershed

1. Linux-based Enterprise Servers
Www.netcraft.com

2. Embedded applications

Linux and Windows are not
Linux is strictly 0 case sensitive
All content in Linux is saved as a file, including hardware
Types of files that are not distinguished by extension in Linux
Compressed package: *.gz *.bz2 *.tar.bz2 *.tgz, etc.
Binary packages. rpm
Web page files. Html. php
Script file. Sh '
Configuration file. conf

Advantages of using the character interface
The character interface consumes less system resources
Character interface reduces the likelihood of an error, being attacked

Primary partition: Can only have up to four
Extended partition

All files in the Linux environment
Hardware Device file name

IDE HDD/dev/hd[a-d]
SCSI/SATA/USB HDD/dev/sd[a-p]
Optical drive/dev/cdrom or/DEV/HDC
Floppy/dev/fd[0-1]
Printer 25-pin/dev/lp[0-2]
Printer Usb/dev/usb/lp[0-15]
Mouse/dev/mouse

Partition Device file name
/DEV/HDA1 (IDE hard drive Interface)
/DEV/SDA1 (Scsi/sara/usb HDD Interface)

Mount
Must partition/follow partition
Swap partition (swap partition, memory twice times, no more than 2GB)
Recommended partitioning
/boot boot partition must be 200MB

After the first installation, there are a lot of features that need to be manually opened, if you use the Ifconfig command can not see the native ip,ping can not be executed, indicating that the matter is not online, need
The CENTOS7 is finally installed in the VMware virtual machine through the following methods: A busy routine yum update found that the CentOS system appears to be the default
Network card is not configured, feedback cannot be networked. After some research, finally let CentOS connected to the net, now announced the method as follows:

Command format

PWD View current directory

[Email protected] ~]#
Root currently logged in user
LocalHost host name
~ Current Directory
# Super User's prompt
$ ordinary user's prompt
Command format
command [options] [parameters]

Note: Individual command use does not follow this format
There are currently multiple options that can be written together
Simplified options and complete options
-A equals--all

ls [options] [file directory]
Options
-a displays all files, including hidden files
-L View more information

Permissions (-L) (-lh show bytes K or m, etc.)
-rw-r--r--.
-(first-) file type (-refers to file D refers to directory, L soft link file)
Each of the remaining three is a group
rw-User Owner
r--User-owned group
r--other people
R Read W write X Execute
-D View Directory properties
-H humanized Display file size
-I display Inode

Directory processing commands
1. Create a Directory

mkdir-p [directory name] -P recursive creation

Eg:mkdir-p China/henan

2. Switch directories

　　

CD [catalogue]   Willing: Change Directory

-Go to the   last catalog CD  . Go to the top level directory CD.  Go to current directory

Relative path: Refer to the current directory to find the "[Email protected]~" # CD. /usr/local/src

Absolute path: From the root directory, first-level recursive lookup. In any directory, you can enter the specified location

such as "[Email protected]~" #cd/etc/

3. View current directory

4. Delete Empty directory

rmdir [directory name]    Delete empty directory

5. Delete files or directories

RM [Options] Directory name or file    name -R Remove directory     -F Mandatory

6. Copy command CP

CP [Options] [Source files or directories] [destination directory] Options     -R Copy directory     -P Joint File property copy     -D If the source file is a linked file, the Copy    link property-A is equivalent to -pdr

7. Cut or rename command mv

CP [Options] [Source files or directories] [target directory]

If cut in the same directory is equivalent to renaming

The role of the common directory

/root directory/bin command save directory (commands that normal users can read)/boot directory startup related files/dev device file save directory//config file save directory/home directory for normal user/lib system library save directory/MNT System mount directory/media Mount Directory

Bin and Sbin in the bin and sbin,usr directories in the root directory are the four directories that are used to save system commands.
The proc and SYS directories cannot be manipulated directly, and both directories hold memory mount points
/root home directory for super users
/tmp Temp directory
/sbin command to save directories that the directory super user can use
Contents of the/var system related documents
/USR system software Resources directory

Connection command

ln-s [Source file] [destination file] hard-link feature: (Can be understood as a classroom two doors, can access data) 1. The block block with the same I node and storage can be considered as the same file 2. Can be identified by the I node 3. Cannot span partitions, 4. Cannot be used for directories

Soft Link Features:
1. Equivalent to shortcuts in Windows
2. Soft link has its own I node and block blocks, but the data is fast only save the source file name and I node number, and no actual file data
3.Irwxrwxrwx I soft link soft link file permission is rwxrwxrwx
4. Modify any one file, and the other changes
5. Delete source files, soft links cannot be used

　　

Linux Learning Notes