One of the linux tutorials

I believe many new users who want to learn linux are wondering what linux learning courses are good. the following small series will collect and organize several important tutorials for you to learn, if you want to learn more, go to the wdlinux school to find more tutorials. 1. what is an RPM Package? RPM is Red... I believe many new users who want to learn linux are wondering what linux learning courses are good. the following small series will collect and organize several important tutorials for you to learn, if you want to learn more, go to the wdlinux school to find more tutorials.
1 What is RPM? Package
RPM is short for Red Hat Package Manager. it is intended to manage Red Hat software packages. as its name suggests, RPM is a software Package management tool contributed by Red Hat; mainstream release versions such as Fedora, Redhat, Mandriva, SuSE, and YellowDog, as well as the release versions developed on the basis of these versions;

What are included in the RPM package? There are other files besides the hosts file;

The application in an RPM Package sometimes requires files of other specific versions in addition to the additional files it carries to ensure its normality. this is the dependency of the software package; the dependency is not exclusive to Linux, and exists in the Windows operating system. for example, if we run 3D games in Windows, a prompt may be prompted during installation, to install Direct 9; Linux and Windows are similar;

CentOS is a Redhat recompilation version, so it is fully compatible with CentOS. wdOS is a simplified version of CentOS and fully compatible.
 
2 , Mysql Database Migration/ Backup/ Recovery and other operations
Mysql is a very good database system. it can be used in Windows or linux. This article just briefly describes some operations in Linux.

Mysql database backup can be performed in multiple ways
1. directly package the directory of database files (I usually use the directory, but the mysql version is required to be the same or similar)
2 mysqldump
3. phpmyadmin
There are also some other tools

In the wdcp background, the database can be backed up, but it is not restored or automatically recovered at present. what should I do when I want to recover it?
The backup directory is in
/Www/backup/mysql
You can decompress the package directly.
Tar zxvf dbname.tar.gz-C/www/wdlinux/mysql/var/
In this way, no operation is required.
Dbname.tar.gz: backup file for the database to be restored
Of course, this is the default
In some cases, you also need to modify the permissions to change the permissions of the decompressed directory to mysql.
For example
Chown-R mysql. mysql/www/wdlinux/mysql/var/dbname
The reason for such modification is that the permission of the original file has been changed because the directory has been moved or uploaded or downloaded. Therefore, you need to modify the permission of the original file. by default, backup recovery is not required.

In the same case, if the migration server is used, you can package, upload, and decompress the package, or directly upload the entire directory to/www/wdlinux/mysql/var.
In this case, you must change the permission. Otherwise, the database cannot be started or the database cannot be written.

After the above operations, do not forget to restart the database, otherwise it may not take effect, as shown in
Service mysqld restart

Remarks
This method is only applicable when the mysql version is the same or similar. Otherwise, there may be other problems.
In this case, you can use mysqldump and phpmyadmin to export and then import the data.
 
3 , Linux Hard disk loading/ Mounting method
Related articles have already said that in Linux, there is no such concept as C and D disks, and some have only directories. everything is based on directories.
The root directory (/) is the most basic directory. there can be many directories below. the root directory can be loaded into a hard disk partition. any directory below can also be loaded into another hard disk partition, this is also a convenient tool for Linux directory structure/hard disk management.



In addition, the hard disk representation in Linux is generally
/Dev/sd (x)
/Dev/hd (x)
....
The above x represents a/B/c/d/e/..., the number of hard disks
Then there is a partition, such
/Dev/sda (x)
Here, x is a number, such as 1/2/3/4/5/..., which indicates the partition number.

For example, if I want to add a new hard disk and connect it to the system
You can use fidks-l to check the name.


For example,/dev/sdb.

If the partition is split and formatted (if not, use the fisk partition)
For example
/Dev/sdb1 is the first partition.

Then I want to load this to the/home directory and how to operate it

Mount/dev/sdb1/home
The above line is finished.
To join the system to start automatic loading, you only need to add it to/etc/fstab, as shown below:
/Dev/sdb1/www ext3 defaults 1 2
This completes all the tasks.


In wdcp, the default software is installed in the/www Directory. sometimes the root directory is insufficient or installed in another partition, you can load the new partition to the/www directory.
As mentioned above, you can change/home to/www.
(Note: This is a new installation, that is, before installation. if wdcp is already installed, this is not the case. for details, refer to the wdcp tutorial)
 
4 , Yum What is
Yum (all called Yellow dog Updater, Modified) is a Shell front-end package manager in Fedora, RedHat, SUSE, and CentOS. Based on RPM Package management, the RPM package can be automatically downloaded and installed from the specified server, and the dependency relationship can be automatically processed. all dependent software packages can be installed at one time without tedious download and installation.
Package source
Software packages available for Yum download include the Fedora package and the Fedora Extras from rpmfusion and rpm.livna.org, all maintained by the Linux community and basically free software. All packages have an independent GPG signature, mainly for your system security. For users of Fedora core 4.0, the rpm.livna.org signature is automatically imported and installed.
Graphical front-end
Yum graphic front-ends mainly include yumex and kyum. They are not independent of Yum, but the Yum graphics front-end. that is to say, they are both based on Yum installation and configuration while installing and using Yumex and kyum; therefore, you must install and configure Yum before using Yumex or kyum.
Common command line commands
Install software (take foo-x.x.x.rpm for example): yum install foo-x.x.x.rpm yum common commands remove software: yum remove foo-x.x.x.rpm or yum erase foo-x.x.x.rpm
Upgrade Software: yum upgrade foo or yum update foo
Query Information: yum info foo
Search software (taking the foo field as an example): yum search foo
For other parameters, see man yum.
 
This document is taken from the wdlinux Forum. For more information, see!