Shell

1. ExercisesWrite a script that calculates the size of all processes in the Linux system and2. Exercise Analysis 2.1. First question, where to collect data for a processUse top or PS to get the memory usage size of each process. Once the size is

1 ${bash_source-$0}Represents the full path of the currently executing script.2 cd-p enters with physical path/usr/localhadoop now chains to the/home/houzhizhen/usr/local/Hadoop/hadoop-2.72

method One: Switch toShellthe directory where the script is located (at this time, called the working directory) executesShellScript:Cd/data/shell./hello.shThe./ means to execute hello.sh under the current working directory . If you do not add

Pstree-p #显示进程编号 (tree) echo $$ basic structure of #显示当前shell进程编号   scripts: #! Shebang (indicates what shell is used to open a file, typically using bash) configuration_variables #定义变量FUNCTION_DEFINITIONS # define function Main_code #主要执行命令  

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

To establish a daemon process:#! /bin/sh PRO_NAME=./xxxx.sh while true ; do #用ps获取$PRO_NAME进程数量 echo ‘‘> nohup.out NUM=`ps aux | grep -w ${PRO_NAME} | grep -v grep |wc -l` #echo $NUM #少于1，重启进程 if [ "${NUM}" -lt "1"

#!/bin/bash#Description: Auto Login The remote server#Author: Majinxu#Version: 1.0#CreateTime: 2018-3-012 18:34:41User= "Majinxu"Passwd= "! Ieric1234 "host_list= ("st1.qa.bj2.yongche.com""St2.qa.bj2.yongche.com""St3.qa.bj2.yongche.com")#seletc the

#!/bin/bashif [[$# = = 0]];thenecho "Error: Please enter the number of days to query???"Elseecho "Temporarily does not support the 7 version of CentOS!!! "now_time_cuo=date +%s((end_time_cuo=${now_time_cuo}- echo $1*3600*24 | bc ))Now_time=date |

Exercise 1:Enter a number to execute the corresponding commandRequirements: Enter a number and then run one of the corresponding commands. The commands shown are as follows: *cmd meau* 1-date 2–ls 3–who 4–pwd; when input 1 o'clock, run date, enter 2

Shell--Unix--Bourne shellBash--linux--Bourne againShellCommand parser function:0 go to specify a path to search for user-entered commands0 environment variable--Path1. command or directory completionShortcut key: Tab1.2. Traverse History

Crontab can execute a shell script and execute a series of Linux commands at a specified timeExample: Server administrator regularly backs up database data, logs, etc.DetailedCommon commands:Crontab–e //Modify the crontab file, if the file does

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

The SED stream editor is also a command in Linux that is often used in the shell to modify the contents of a file in a non-interactive way. The SED handles the text in rows, that is, one row at a time.The basic format of the SED command is:sed

The following is a syntax format for input and output redirection Two overview Output input redirectionGreater than sign >: Indicates output redirection (overwrites the original file)Less than Double greater than sign >>: (indicates output

#!/bin/bash#第一次运行创建记录文件-f 1.txt || touch 1.txtwhile :do #查看日志中登陆失败的ip次数超过10次的用户ip fip=`awk ‘/Failed/{ip[$11]++;}END{for (i in ip){if (ip[i]>10){print i}}}‘ /var/log/secure` #循环取出登陆失败超过十次的ip进行处理 for i in $fip do #查看处理记录文件如果该ip没有存在处理记录中说明是没有处理过该ip

Note Using expr:The operator and the number used for the calculation have at least one space around it, otherwise the errorWhen using multiplication sign, a backslash must be used to mask its specific meaning.An enterprise-class case study of

One: Word accumulationCurrent: currentlyDirectory: Directories Entries: ArticlesDefault: DefaultsInformation: InformationFormat: FormattingIgnore: NeglectLicensing: LicensingTwo:1.GNU Bash Description: The shell is the user interface of the Linux

The first is to find the file name by using a-name parameter.Query for files ending in. txt, and files that begin with T :[Email protected]:~/test$ lsone.txt three.txt two.txt[email protected]:~/test$ Find/-name ' *.txt './two.txt ./one.txt./three.

Shell Special Symbols1.cut command:[[email protected] ~]# cat /etc/passwd |head -2 |cut -d ":" -f 1rootbin[[email protected] ~]# cat /etc/passwd |head -2 |cut -d ":" -f 1,2root:xbin:x[[email protected] ~]# cat /etc/passwd |head -2 |cut -d ":" -f

Shell programming-detailed explanation of the while & until loop (Code instance), shellwhile Loop statement commands are often used to execute a command or a group of commands, so they are stopped when the conditions are not met. In shell scripts,