Shell

Classification ReferenceFile Status Test -B filename Returns True when filename exists and is a block file (returns 0) -C filename Returns True when filename exists and is a character file -D

#一个shell的启动流程 #shell have some variables, called environment variables, which can be inherited, #比如父shell有 $UID, child shells can have, and inherit the parent shell. #正常我们声明一个变量, a=1, in the child shell, A is empty, and the variable declared by

[Email protected] wyb]#CatTest.SH Echo-E"\033[32mhello,this is Wangyuebo ' s shell\033[0m"Echo-E"\033[32m ' Date ' \033[0m"LANG=enEcho-E"\033[32m ' Date ' login at ' hostname ' W ' \033[0m">>/etc/Wangyuebo.log[[email protected] wyb]# when the cue is

View System available Shell types: (typically bash shell)? ~ Chsh-l/bin/sh/bin/bash/sbin/nologin/bin/Dash/bin/zshTo modify the current shell:[[email protected] ~]# Chsh-l/bin/sh/bin/bash/sbin/nologin/bin/Dash /bin/~ for root. New Shell [/bin/bash]:/

Reprint please indicate http://www.cnblogs.com/winifred-tang94/There are three types of variables in the shell environment:A, environment variables; You can refer directly to the shell script in the form of "environment variable name".b,

Shell variables: Local variables and environment variablesBasic elements:#！ /bin/bash#VariableProcess ControlHome: The current user's home directoryPath: The current user's executable file search pathLANG: The default language the program should

Zookeeper under the shell operationEnter%zk_home%/binperform zkcli.sh [-server Ip:port] #如不指定, then connect the nativeCreate:create [-S] [-e] path data ACL #创建数据节点-----s indicates that the sequential node-e represents a temporary node, and two are

character class (Character Class): The above example x and y, which represent one character in the pattern , but the range of values is a class of wordsAny one of them.Quantity Qualifier (quantifier): each part of a mail address can have one or

Eval syntaxEval arg1 arg2 ...The function of Eval is to take the following parameters Arg1 Arg2 and so on as a pipeline, and then re-execute the shell process pipeline (about pipeline, see http://www.cnblogs.com/chaoguo1234 /p/5724321.html)Suppose

Create two scripts in the system bin directory, respectively, Pssh tsshPssh#!/usr/bin/expect-fSet IP [lindex$argv 0]set Port [lindex$argv 1]set Password [lindex$argv 2]set TimeoutTenspawn ssh [email protected]$ip-P$portExpect {"*yes/no"{Send "yes\r";

Script Programming:Sequential structureSelect structureIfCaseLoop structureForWhileUntilWhile loop: For scenarios where the number of cycles is unknown, exit conditions are neededGrammar:While CONDITION; DoStatement...Done Calculates the and of all

Shell Footstep Source code:[Email protected]_ecs imooc_shell]$ lscheck_http_log.sh check_nginxserver.sh master_control.sh system_info.shMaster_control.sh: The main control footsteps, other footsteps this script calls##################################

Special usage One whileSyntax Formatwhile read line; DoLoop bodyDone Function: Reads each row in the/path/from/soemfile file sequentially and assigns this line to the line variableExample: Scan a/etc/passwd file for each row, if the Discovery gecos

There are two ways of doing this:1, with TRExample: uppercase=$ (echo $VARIABLE | tr ' [A-z] ' [A-z] ') (convert VARIABLE lowercase to uppercase)lowercase=$ (echo $VARIABLE | tr ' [A-z] ' [A-z] ') (convert VARIABLE uppercase to lowercase)2, with

Progress barC Language progress bar reference my original article blog-> progress barFunction proc () {     i=0      str= '       arr= (' | ')   '/'   '-'   ' \ \ ')      index=0     while [   $i  -le 100 ]     do          printf  "[%-101s][%d%%][%c]

      declare -i noar= (1 1 1 1); Br= (1 1 1  1 1 1 1 1 1 1    1 0 0 0 0 0  0 0 0 1    1 0 0 0 0 0 0 0 0  1    1 2 0 0 0 0 0 0 0 1     1 0 3 0 0 0 0 0 0 1    1 0  0 4 4 5 0 0 0 1    1 0 0 0 0  0 0 0 0 1    1 1 1 1 1 1 1 1  1 1) echo  "[][]|" echo  " 

Overview:Statement control for Shell scripts-There are three processes in the process programming language mentioned earlier:Sequential execution: Executed in the order of a single statement;Select execution: Select execution according to the

• printenv– Print Some or all of the environment variables• set– set shell options• export-Export the environment variables so that the program that is executed later knows.• alias– create command aliases1.shell Environment: The shell maintains a

Exercise one: Write a script 1. Set the value of the variable file to/etc/passwd 2. Say hello to each user in/etc/passwd, and say what the ID is like: (Hint: line= ' wc-l/etc/passwd |       Cut-d ""-f1 ') Hello,root,your UID is 0. 3. Count the

The difference between an array and a variableVariables: Storing the memory space of a single elementArray: A contiguous memory space that stores multiple elements, equivalent to a collection of multiple variablesArray = array name + indexIndex: