1. Evolution of system initialization technology - boot process
CentOS 6: Adopting INIT technology, the entire boot process is self-checking BIOS - MBR boot - GRUB loads - loads the kernel - starts the INIT process - reads the INITTAB configuration file and starts the process services in order according to the mode specified in the configuration file. INIT technology makes the startup process very clear and relies on SHELL scripts. Because the processes are started one by one in sequence, the speed is slow and the system startup may be affected because a certain service is stuck.
CentOS 7: Using systemd technology. This is a new technology that replaces INIT. It uses a parallel method to start the process, so the startup speed is faster, and it is compatible with INIT commands to reduce migration costs.
PS: You can know the technology used by the current system by viewing the process with PID 1 through the ps command.
(Recommended tutorial: centos usage tutorial)
2. Changes in network setting methods
The familiar ipconfig in CentOS 6 is used in CentOS 7 was replaced by the ip command; the graphical network configuration tool nmtui replaced setup
3. Host name and character set
In CentOS 6, you can modify the host name by editing /etc/ sysconfig/network file, but this method has been abandoned in CentOS 7, and the /etc/hostname file is used. The method of temporarily modifying the host name remains unchanged, and the hostname command is still used. And a new hostname management tool hostnamectl has been added to CentOS 7 (the file name modifications made by this tool are permanent).
For the modification of the character set, CentOS 7 uses the new configuration file /etc/locale.conf to replace /etc/sysconfig/i18n. If you want to temporarily modify the character set, the method remains the same, modify the LANG variable, such as LANG=zh_CN.UTF-8. A new character set management tool, localectl, has the same effect as hostnamectl.
4. Compatible with /etc/rc.local
The /etc/rc.local file records commands that need to be automatically executed after booting. Although this file has been abandoned in CentOS 7, However, it can also be used with compatibility. You only need to give the file executable permissions:
chmod +x /etc/rc.d/rc.local
5. The difference between runlevels
The /etc/inittab file in CentOS 6 is based on init technology. , so naturally it cannot be used in CentOS 7, but the file is still retained, but the content has been replaced with boot content to let users know how to switch run levels now. Since this is not commonly used, I will not continue to describe it.
6. Service Management
This is the most unpleasant modification for users. It adds the systemctl tool and integrates the functions of service and chkconfig commands. See the figure for specific usage:
Related video tutorial sharing: linux video tutorial
The above is the detailed content of The difference between centos6 and 7. For more information, please follow other related articles on the PHP Chinese website!

查版本号的命令:1、“cat /etc/issue”或“cat /etc/redhat-release”,可输出centos版本号;2、“cat /proc/version”、“uname -a”或“uname -r”,可输出内核版本号。

centos重启网卡的方法:1、对于centos6的网卡重启命令是“service network restart”;2、对于centos7的网卡重启命令是“systemctl restart network”。

centos php安装opcache的方法:1、执行“yum list php73* | grep opcache”命令;2、通过“yum install php73-php-opcache.x86_64”安装opcache;3、使用“find / -name opcache.so”查找“opcache.so”的位置并将其移动到php的扩展目录即可。

centos离线安装mysql的方法:1、将lib中的所有依赖上传到linux中,并用yum命令进行安装;2、解压MySQL并把文件复制到想要安装的目录;3、修改my.cnf配置文件;4、复制启动脚本到资源目录并修改启动脚本;5、将mysqld服务加入到系统服务里面;6、将mysql客户端配置到环境变量中,并使配置生效即可。

centos7安装不出现界面的解决办法:1、选择“Install CentOS 7”,按“e”进入启动引导界面;2、 将“inst.stage2=hd:LABEL=CentOS\x207\x20x86_64”改为“linux dd”;3、重新进入“Install CentOS 7”,按“e”将“hd:”后的字符替换成“/dev/sdd4”,然后按“Ctrl+x”执行即可。

centos删除php的方法:1、通过“#rpm -qa|grep php”命令查看全部php软件包;2、通过“rpm -e”命令卸载相应的依赖项;3、重新使用“php -v”命令查看版本信息即可。

我们的PC中有一个磁盘驱动器专门用于所有与Windows操作系统相关的安装。该驱动器通常是C驱动器。如果您还在PC的C盘上安装了最新的Windows11操作系统,那么所有系统更新(很可能是您安装的所有软件)都会将其所有文件存储在C盘中。因此,保持此驱动器没有垃圾文件并在C驱动器中拥有足够的存储空间变得非常重要,因为该驱动器拥有的空间越多,您的Windows11操作系统运行起来就越顺畅。但是您可以在磁盘驱动器上增加多少空间以及可以删除多少文件是有限制的。在这种情况下,

方法:1、利用“vim ~/.bashrc”编辑用户目录(~)下的“.bashrc”文件;2、在文件内添加“alias ls="ls --color"”;3、利用“:wq!”命令保存文件内的更改;4、“exit”命令退出终端后重新连接即可。


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