Shell

In order to locate the problem, we need to locate the running log or error message of the task.When some scripts are called through the shell, the log information is printed in the shell. However, there are users in the shell call normal, but to

To run an app on the spark cluster, simply pass through the master's Spark://ip:port link to the Sparkcontext constructorRun the Interactive Spark command on the cluster and run the following command:Master=spark://ip:port./spark-shellNote that if

use the For loop to bulk create 10 HTML files in the/oldboy directory, where each file needs to contain 10 random lowercase characters plus a fixed string oldboy, with the following name examples:[[email protected]]# ls/oldboyapquvdpqbk_oldboy.html

Video link:1. What is shell script (script written by Shell)1.1 Why study shell scripts? ()1.2 Writing and execution of the first script1.3 Creating a good habit of writing shell script2. Simple shell Script Exercise: (read-p date)3. Use the

The R-parameters of the LS command represent a recursive listing of all the files in all subdirectories, and 1 means that each row shows only one file or directory, and F means that the output is not sorted. F represents the end of each item's

The read command is used to receive input from the keyboard's standard input and other files, and after the input is entered, the Read command places the data in a standard variable.Example 1:#!/bin/bashRead-s-P "Enter you password:" Password #-s:

Special variablesEnvironment variables:The system itself runs a class of variables that need to be created in advance by the Linux systemMainly used for the user's working environment, including (user's host directory, command lookup path, user's

One: RANDOMEcho $RANDOMRandom number is a range of 1--32767, generally used it can be cracked1.2 Generate a eight-digit random password:echo $ (($RANDOM +11111111))Two: Md5sum random encryption method generates a longer passwordTake 9-digit password:

One: RANDOMEcho $RANDOMRandom number is a range of 1--32767, generally used it can be cracked1.2 Generate a eight-digit random password:echo $ (($RANDOM +11111111))Two: Md5sum random encryption method generates a longer passwordTake 9-digit password:

Shell Scripting Features:Connect MySQL, create the database automatically, the script is as followsMysql-h$mysql_ip-u$mysql_user-p$mysql_password--default-character-set=utf8-e "CREATE database IF not EXISTS test"Database IP, user, password using

Due to the need to manually install SBT for the first time, networking is required, so the network adapter mode of the virtual machine is set to "bridge mode" so that it can be connected to the Internet.However, when the "Spark-shell--master

First line: #!/bin/bash--#! Interpreter for Tag scriptScript: #!/bin/bashecho "Hello World"Give execute permission chmod +x./test.shExecute script:./test.shThe $ symbol is not required when defining a variable: td= ' Date ' +%y%m%d '1. There can be

Shell combined with expect auto-input Password example1#!/bin/Bash2 3cd/data/Live4 5/usr/bin/expect EOF6Spawn git clone"ssh://xxxxxxxxxxxx"7Expect"*passphrase*"8Send"passwordhere\n"9 expect EOFTen EOF One A Time= '/bin/Date "+%y%m%d%h%m%s"` -CD

1. Command history:Environment variables:Histfile: Number of records in the command historyHistsize:~/.bash.historyHistfilesize: The number of history records in a command history fileHistory: Default display of 10 recordsHistory-n: Show post n

A shell script is a function that uses the Shell's command interpretation to parse a plain-text file and then perform these functions, or it can be said that a shell script is a collection of commands.The shell can be used directly above the

Because my normal working environment is Linux, so inevitably use command line mode and shell script, and some command line every day to lose many times, such as SSH login, so simply put the usual commands are written script files, so deliberately

#! /bin/shLook for Shell interpreter/bin/sh is a path#! /usr/bin/pythonJust looking for a Python interpreter.Ways to execute a Linux program:Enables the file to execute directly with executable permissionsInvoke the interpreter to runUse Source to

Article from my personal blog: (Linux shell) Chapter II-The Joy of command (a)In the previous chapter, we described some of the syntax that some Linux shells need to be aware of. Next we begin to understand the frequently used commands of the Linux

Functions: functionProgram Programming: Code ReuseModular programmingStructured programmingThe code of an independent function as a whole, and a name for it; a named code snippet, which is a function;Note: The code snippet that defines the function

Shell reads each line of the fileWriting one:----------------------------------------------------------------------------#!/bin/bashWhile Read lineDoEcho $lineDone ----------------------------------------------------------------------------Two:------