Shell

The command line can execute multiple commands at once, in the following ways:1. Separate each command;Note: The execution of each command will not affect the execution of other commands. In other words, each command executes,However, there is no

Determines whether the current user is the root administrator, and if so, executes the tar to perform a backup of the/etc/directory.#!/bin/bash# IF Current user was root then backup the/etcIf ["$ (id-u)"-eq 0];thenTar-czf/root/etc.tar.gz/etc

Shell scripting is the most basic knowledge of our OPS management, and here are a few examples of my learning process (compared to Daniel). The purpose of this blog is to record the course of learning scripts, but also to be able to discuss learning

Question 1: [[Email protected] ~] # Cat ABC 1aabbb2ccddd3eefff4gghhh Change 1aabbb2ccddd3eefff4gghhh Implementation command: Sed '/[0-9]/n; S/\ N //;/[A-Z]/n; S/\ N //; n; D' ABC Question 2: [[Email protected] ~] # Cat ip.txt 172.16.1.10

   Remote SCP file by using reverse CT in shell script: Before using reverse CT, you need to install two RPM packages: # rpm-ihv centos/expect-5.43.0-5.1.i386.rpm # Rpm-ihv centos/expect-devel-5.43.0-5.1.i386.rpm or yum directly download and install

Common shell script interpreters in Unix/Linux include bash, sh, CSH, and KSh. Bash is the most common interpreter in Linux. Script Language isInterpreted languageWhen executing such programs, the interpreter (Interpreter) needs to read the source

I. Condition statements 1, If [expression] Then # Code block Fi 2, If [expression] Then # Code block Else # Code block Fi 3, If [expression] Then # Code block Else if [expression] # Replace this field with Elif [expression] Then # Code block Else #

#! /Bin/bash Hello = "var1" Echo $ hello Function func1 # define function func1 { Local Hello = "var2" # define the internal variable hello Echo $ hello } Func1 # Call a function Echo $ hello Execution result: Conclusion: local variables only work

Echo-e "\ e [1; 31 m This is red text \ e [0 m" \ E [1; 31 m set the color to red, \ e [0 m "will reset the color. Each color has a corresponding color code, resetting 0, black 30, red 31, green 32, Blue 34, Magenta 35, cyan 36, white 37 To set

1. you can set the number of servers to be checked and the server to check. You can set the IP address of the non-Online host and the corresponding time of the non-Online host, and collect statistics on the number of non-Online hosts saved to the

It is easier to parse and modify XML using python, but if it is not convenient to use python, you can simply replace it with the SED command For example, to replace the value of the port number in the following line: 21 You can use: New_port =

Traditional if statements -- use conditional expressions as if conditionsIf [conditional expression]ThenCommandCommandCommandElseCommandCommandFiConditional expressionsFile expressionIf [-F file] If the file existsIf [-d...] If the directory

In shell programming, some string variables are often processed. For example, commands such as awk, expr, sed, and TR are often used to calculate length, intercept substring, and replace character. Next we will introduce a simple string processing

In Linux, shell variables $ #, [email protected], $0, $1, $2 are interpreted as follows:Variable description:$Shell PID (processid)$!PID of the background process last run by Shell$?End code of the last command (return value)$-Flag overview set by

Linux logging method:Tee-a aa. log #-A indicates appendGrep "fdongdfd" missiles 2> BB. log error output to BB. LogCat aa.txt bb.txt 1> biaozhun.txt 2> cuowu.txt standard output to biaozhun.txt error output to cuowu.txtCat aa.txt bb.txt> error.txt 2>

Start:The URL of svnis in excel. I copied it to txt.pdf, while VIOs only extracted the URL and saved it as url.txt.You can use VI to process url.txt, add SVN checkout, and other words to become the svn. Sh that can be run. Each row isSVN checkout.../

File descriptorBefore a process reads a file, it needs to open the file. When the process opens the file, Linux associates the file with a number (called a file descriptor ), the file descriptor is an index of the opened file in the input table.

String truncation method in shell programming: 1. the GNU Linux Shell intercepts the first eight characters of the character variable by using the following methods: 1. expr substr "$ A" 1 8 2. Echo $ A | awk '{print substr (, 1, 8 )}' 3. Echo $ A |

./Bin/spark-shell -- master spark: // master: Port StartCluster mode: Master = spark: // 'hostname': 7077 bin/spark-shellbin/spark-shell -- master spark: // es122: 7077 standalone mode: bin/spark-shell local [4] loads a text file spark context

Preface when using bash shell to write a program, the for loop is often used, especially the requirement from 1 to 100. Here we record the C language of several types of loop methods from 1 to 100 in shell. [HTML]View plaincopyprint? For (I = 1; I