1-1. Common commands for databases and RedHat Linux

1. Mainstream Databases

Currently, the mainstream databases used in software development process include Oracle, DB2, SQL Server, and MySQL. They have their own characteristics, the differences are as follows:

ORACLE: Oracle is the core product of Oracle. It can run on all mainstream platforms (including windows) and has the highest level of ISO certification in terms of security. Today, the largest database market share is the largest, it has the highest concurrency, the best efficiency, the highest performance, the highest charges, and a high price. It is suitable for large projects of large companies.

DB2: The concurrency and efficiency of IBM's large database products are not as good as that of Oracle, but the core advantage is the powerful data processing in the background, which is also expensive. It can run on all mainstream platforms (including windows) and is most suitable for projects with massive data volumes. It features high online transaction processing performance and has the highest level of ISO certification in terms of security. Large financial-related projects may use two types of databases. Oracle is the first to handle concurrency, and DB2 is responsible for data processing.

SQL Server: Microsoft products can only run on Windows. The interface is friendly, without any openness, and no security certificate is obtained. It is suitable for small and medium-sized projects if multiple users have poor performance.

 

MySQL: Oracle was incorporated into ORACLE after sun was acquired. It is widely used in small and medium-sized projects, and even large projects use it for database clusters. It is basically free of charge, suitable for personal websites and website applications of some small enterprises.

2. Common RedHat Linux commands

Man RM (Rm -- Help)
View help

CD
Enter the Directory

PS-Ef | grep Java
View Processes

Pstree | grep Java
View process tree

Kill somepid
Kill a process

Kill-9 $ (PS-Ef | grep udpserver | grep Java | awk '{print $2 }')
Delete A udpserver Process

Rpm-AQ | grep PHP
View installation media

PWD
View Current Directory

Ls-l-T
-L display details,-t sort by Time

Ll
Equivalent to LS-l

Find/-name libnativemethod. So
Equivalent to ll | grep somefile

Grep sometext *
Search for all text in the current directory

Ifconfig
IP Address Configuration. You can use the setup command to start the character interface.

Chmod A + x somefile
All users can execute

Chmod U + x somefile
The current user can execute

Env
Environment configuration, equivalent to set in window

Env | grep path
View environment variables

Export
Equivalent to set classpath

Echo
Output variable name

Netstat-NPL
View port

Lsof-I: 22
View port Process

CP from
Copy an object

CP-Fr./j2sdk1.4.2 _ 04/usr/Java
Copy directory

Mkdir
Create directory

MV
Cut or rename

Rm-R
Recursive deletion.-F indicates force.

> Somefile
Clear File Content

Which Java
View the directory corresponding to the Java Process

Who
Show current user

Users
Show current session

Zip-r filename.zip filesdir
Zip a folder

Unzip somefile.zip
Decompress the ZIP file to the current directory.

Gunzip somefile.cpio.gz
Decompress. GZ

Cpio-idmv <somefile. cpio
Cpio operations

PS auxwww | sort-n-r-k 5 | head-5
Sort by resource usage. The first 5 indicates the number of columns, and the second 5 indicates the first few

Hostname-I
Displays the host machine name, adds I, and displays the IP address of ETC/hosts.

Rpm-IVH some. rpm
Install software

Rpm-uvh some. rpm
Update Software

Rpm-Qa | grep somesoftname
Whether a software has been installed

Tar-xvzf some.tar.gz
Extract package

Tar-cvzf some.tar.gz filedir
Compress the package

Shutdown-I6-Y 0
Restart the server immediately

Reboot
Restart the server immediately, equivalent to shutdow-R now

Halt
Shutdown immediately, shutdown-H

Shutdonw-R

Shutdown-R + 15

Shutdonw-R + 30
Timed restart

Gdmsetup
Start the system configuration management interface, which must be executed on the GUI

Setup
Start the text Configuration Management Interface

VI/etc/sysconfig/Network
Modify the machine name, and then restart the machine or service network restart.

Locale
Display System Language

Export lang = zh_cn.gbk
Set the system language to solve consol Chinese garbled characters

Ln-s src_full_file the_link_name
Create soft link

Last
View logged-in user history in reverse order

History
View History commands

Tail-10 somefile
View the last 10 lines of the file

Head-10 somefile
View the first 10 lines of the file

Tail-F somefile
View File Content in real time for debugging

Date-s 10/09/2009
Modification date

Date-s 13:24:00
Modification time. date is displayed directly.

DF-K
View File disk space

DF-V
View a file space

Du
View disk space usage

Free
View memory usage

Top
View the current system resource usage

Vmstat 5 10
Refresh once in less than 5 seconds, refresh 10 times; time, Timex, uptime, iostat, SAR

CAT/proc/cpuinfo | grep processor | WC-l
Obtain the number of CPUs

Service mysqld start
Start the MySQL service.

Service mysqld stop
Stop MySQL Service

Serice mysqld status
Display MySQL service status

Service-status-Al
View existing services

 

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