Linux

1. Touch filename To create a new file2. Readlink-f filepath trace the true file path of the symbolic link3. Id-u gets the ID of the current user, if the ID is 0, it is the root user, otherwise the general user4. Echo $? Outputs the end state of the

Sed is a good file processing tool, itself is a pipe command, mainly in the behavior of the unit processing, you can replace the data rows, delete, add, select and other specific work, the following first understand the use of SEDThe SED command

"description" Today looked at jetty this web container, the morning to see the basic theory framework knowledge (the slightest useless to the back), the afternoon downloaded jetty, and deployed a war application on the above, at night in the

1. When using the remote terminal, the following command can be used:ScreenTmux2, download the file can use the following command:CurlWget3, compression decompression can be used:tar, zip, rar4. Use Grab Bag toolTcpdump5. String Processing toolAwk6.

Enter the systemGeneral User studnet:Click Student Enter password to enter the normal user studentSuper User root:Click >not ListedEnter Superuser username >rootType the password >********Language adjustmentApplications----->system

May be a preconceived idea, many people think that the Linux system shape is not practical, in fact, this is wrong, usually the server does not use the graphical interface, the graphical interface is really useless, but if the Linux server is used

System boot is the beginning of operating system operation, before the user can log on to the system, the Linux boot process completed a series of initialization tasks, and load the necessary programs and command terminal, for the user to be ready

Firewall Basic Concepts:1, the firewall work at the host edge: for the access to the network or the host of data packets, according to the pre-set check rules for its inspection, suspicious of the messages are in accordance with the pre-defined

What I have written here is what I have come across and remember.1, the first floor/--root directory/boot--boot directory, storage system boot files and some kernel files/root--House/etc--directory for System configuration

LVM is a logical mechanism for the management of disk partitions in Linux system, which is built on the hard disk and partition, a logical layer under the file system, to block the partition layout of the lower layer when the file system is set up,

the time of Linux is divided into system clock and real time clock (hardware, or RTC). system time: Refers to the time in the current Linux kernel. hardware time: battery-powered time on the motherboard. command to view system time: #datecommand to

Under Linux, run CRONTAB-E* * * * */usr/local/php/bin/php/your_project_path/yii test/testThe above example shows that 21:30 per night executes the above timed programHere are some basic introduction to timed task settingsBasic format:* * * * *

The following is a CentOS 7 example:Startup level ModificationSystemctl Isolate Multi-user.targetSystemctl Isolate Runlevel3.targetstartup files in/etc/systemd/system/default.targetYou can change the file directly if you want to modify

Variable: A memory space for storing information such as characters, numbers, and so on.Array:How to declare an array:Assignment Method 1:Aa[0]=jerryAa[1]=tomAa[3]=wendyAa[6]=natashaAssignment Method 2:Aa= (Jerry "Tom Obama" Wendy Natasha)Aa=

Search engine Elasticsearch 5.2.2 in the WIN8 installation process is as followsDownload elasticsearch5.2.2 HTTP://PAN.BAIDU.COM/S/1I5BS5NVExtractOpen and configure the Elasticsearch/config/elasticsearch.yml filecluster.name:es-clusternode.name:node-

Install CentOS 7 yum source in redhat 7, centosyum Because the redhat update package only takes effect for registered users, You need to manually change it to the CentOS update package,CentOS is almost the same as redhat, so you don't have to worry

Centos-based freeradius high-availability lvs (UDP) and freeradiuslvs I recently configured freeradius for high availability and used lvs vip for polling: For freeradius configuration, see the previous article; The configuration of keepalived in lvs

Kafka ~ HelloWorld is not easy to get. kafkahelloworld Today, the zookeeper and kafka environments are connected and deployed successfully. However, with the. net driver, the consumption is not successful. Why? The first thought was the reason, so

Install zabbix on cent 7 and zabbix on cent 7 I have not written any essays before. This is the first chapter and the first time. The following describes how to install zabbix in cent 7 for your reference only: System: cent 7Zabbix

Detailed explanation of linux sort commands (transfer) and linuxsort commands The sort command is used to sort data based on different data types. Its syntax and common parameter formats are as follows:Sort [-bcfmnscn] [source file] [-o output