Comprehensive explanation of environment variable configuration in Linux (principle + method)

Experimental environment Alibaba cloud server Linux centos7 Applicable to all Linux distributions (CentOS, Ubuntu, etc.) and embedded Linux principle environment variable The export command can display all current environment variables [root@shuaifriend ~]# export declare -x HISTCONTROL="ignoredups" declare -x HISTSIZE="1000" declare -x HOM ...

Posted by lucasrd on Tue, 24 May 2022 00:18:01 +0300

Nginx method for configuring multiple HTTPS domain names

I've been playing wechat applet recently. I have: One ECS: CentOS 7 Multiple primary domain names During the development and testing process, for some reasons, you want to make the domain names A and B point to port 443 of the ECS at the same time and support HTTPS. Nginx supports SNI extension of TLS protocol (multiple domain names with diff ...

Posted by the-botman on Tue, 24 May 2022 00:03:36 +0300

In Shell script, $0, $?, $!, $$, $*, $#$@ And the meaning of linux command execution return value

In Shell script, $0, $?, $!, $$, $*, $#$@ And the meaning of the return value of linux command execution   (1) In shell script, $0, $?, $!, $$, $*, $#$@ And so on 1.1 brief description   ps: you can understand it by trying more in Linux environment $$ The PID (ProcessID) of the Shell itself, that is, the current time the script is running Proce ...

Posted by frenchy373 on Mon, 23 May 2022 23:56:09 +0300

Bash trick: Shell script that can move and rotate Tetris left and right

In Linux bash, the previous article introduced a shell script that uses the k, j, h, l keys to move a single block up, down, left, and right. The following continues to describe how to rotate a single block. Execution effect The specific implementation effect is as follows: Screenshot before rotation Screenshot after moving and rotating When ...

Posted by hammadtariq on Mon, 16 May 2022 21:58:38 +0300

Shell Programming Specification Variable Details (shell programming specifications in Linux, how scripts are executed, pipe symbols and redirections, shell variable types)

Preface Shell is a program written in C that serves as a bridge for users to use Linux. Shell is both a command language and a programming language. _The execution of Linux commands must depend on the shell command interpreter. Shell is actually a special program that runs in the Linux operating system. It is located between the kernel of ...

Posted by simonmlewis on Sun, 15 May 2022 20:50:07 +0300

linux judgment command test solution

The judgment command test can be abbreviated as brackets []. It can be divided into string judgment and general judgment. Note that there must be spaces between the brackets [] and the judgment conditions, and between the judgment symbols of the judgment conditions and the comparison value. If test is used alone, if the judgment condition is t ...

Posted by Smeep on Sun, 15 May 2022 08:44:35 +0300

Alibaba cloud proprietary cloud container service elastic scaling best practices

Introduction: Alibaba cloud proprietary cloud container service elastic scaling best practice 1. Introduction to elastic expansion of container service This section will briefly describe the elastic scaling of container services based on the principle of use.This practice is based on the K8s business cluster running on the private cloud to con ...

Posted by jv2222 on Sat, 14 May 2022 01:05:01 +0300

1, shell concise notes

catalogue 1 shell introduction 2 shell syntax 3 shell formatted output 4 shell basic input 5 variables 6 array 7 shell process control if judgment statement 8 shell process control for loop statement 9 loop control statement 10 shell process control while loop statement 11 until statement 12 case multi conditional branch statement 13 shell s ...

Posted by robogenus on Fri, 13 May 2022 11:42:26 +0300

Shell command execution visualization and alerting tools

Sampler is a tool for shell command execution, visualization and alerting. Its configuration uses a simple YAML file. 1. Why do I need it? You can sample any dynamic process directly from the terminal - watch for changes in the database, monitor MQ in-flight messages, trigger deployment scripts and get notified when it's done. If there is a wa ...

Posted by jarriola on Thu, 12 May 2022 10:38:39 +0300

Advanced shell Programming Notes (Chapter 31 Gotchas)

Chapter 31 Gotchas Declare reserved words and characters as variable names case=value0 #Raise error 23skidoo=value1 #Raise error #Variable names that begin with numbers are reserved for use by the shell #Try_ 23skidoo=value1. Variable names starting with an underscore are allowed #But It is also not possible to use only underscores as v ...

Posted by the apprentice webmaster on Mon, 09 May 2022 02:37:38 +0300