Shell

-silent     is used to eliminate the default display of Sql*plus and database version information   when the login Sql*plus is connected to the database, and also removes the display prompt.             can be shortened to-sset pagesize 0  

In general, case is a judgment statement that is easier to understand than if.Case Statement Formatcase in 变量 值1) 内容 ;;值2) 内容 ;;esacNote: Each content needs to be added after;; , can be written across rows or peers. Instance: Executes

10.1 Commond: Suppress normal shell function lookups 10.2 exec: Replacing the current shell process with the Execute command 10.3 Bash:gnu's Bourne-again shell interpreter 10.4 Builtin: Execute shell built-in command 10.5 Enable:

The VI editor has three status modes "VI file name (or path + file name)"1. Command mode2. Input mode3. Last-line modeConversion between three modesVi. start and exit of the VI editorGo directly to the editing environment$ VIEnter the editing

Executes the command and uses the command state return value to determine certain statesecho $?0 stands for Success, not 0 for unsuccessfulTo test an expressionNumerical comparison-eq equalsThe return value is 1, indicating 2 is not equal to 3-ne

If statement1. What is a conditional test operation?To make a shell script "intelligent", the problem is to differentiate between different situations to determine what action to take. The shell environment, based on the return status value ($?)

DirectoryI. Condition selection: If statementTwo. Conditional judgment: Case statementThree. For loopI. Condition selection: If statement Single Branchif judgment condition; thenBranch code with true conditionFiExample: Judging whether a number

1. Limitations of single-quote strings: Any character in a single quotation mark is output as is, and the variable in the single-quote string is not valid; Single quotation marks cannot appear in single quote strings (not after using escape

1. Special symbolsFor more information, see2, about the pipe character(1), cut split-D delimiter-F Specify segment number-C to specify the first characterFor example, see,Example, | Output, cut splits out the desired results later. In general,-C and-

Exercise 1:User interaction ScriptsRequirements: write a script that, after execution, prints a line that says "Please input a number:", asks the user to enter a value, prints out the value, and then asks the user to enter the value again. Until the

Shell Variables1. Order env to list all system variables (all uppercase letters) of system presets2. The command set can see the variables that are preset by the system, or you can see the user-defined variables.3. Custom variables:Rules for

File Test OperatorsFile test operators are used to detect various properties of Unix files.Attribute detection is described as follows: operator Description Example -B File Detects if the file is a

 Introduction to the Shellzsh, ksh (yum list |grep zsh to be viewed and then installed accordingly )Command history1./root/.bash_history (this file holds the command we've knocked on)2. History (You can see how many of the commands we've used before.

There is the following text, where the first 5 lines of content are1,111,111:13,443,253,4562,222,222:13,211,222,1221,111,111:13,643,543,5443,333,333:12,341,243,1232,222,222:12,123,123,123After processing with the shell script, output in the

Exercise 1:Backing Up the databaseRequirements: Design a shell script to back up the database, first save a copy of the data on the local server, and then remotely copy a copy, save the week of data locally, Remote Storage for one monthsAssume that

LNMP stands for: Linux system nginx+mysql+php this site server architecture. LNMP is now the most large companies in the Web environment, Nginx Small and efficient Web server and reverse proxy server, compared to Apach occupies less resources, more

File expression-e filename true if filename exists-d filename If filename is a directory, true-F filename True if filename is a regular file-L filename True if filename is a symbolic link-r filename If filename is readable, true-W filename if

1. The return value of the Shell function:In general, a return of 0 indicates a successful run, and a non-0 return indicates a failure. For a view of the return value, use the $? command.2. Incoming parameters for Shell functions:Use the location

Multiple values can be stored in an arrayThe shell array is represented by parentheses, and the elements are separated by a "space" symbol.Syntax format:Array_name= (value1 value2 ... valuen)Defining

Shell script sum (Code instance), shell script sum instance The principle is as follows: 1) define two variables I, sum, both initialized to 0 2) define a loop body, calculate the sum. 3) Use let $ sum = $ sum + $ I to replace the value. 3) sum of