Shell

Problem Description In the "[]" test, the result of the judgment is always true for reasons not known.For example: ["$choice" = = "n"-o "$choice" = = "n"] && echo-e "Oh interrupt!" && exit 0 Regardless of what the variable "choice" is, the test

A shell process is a process that executes other processes, but when a command is executed, the shell process instructs the kernel to execute the specified program separately as another process and write the output to the terminal. With the command

In operation, you will encounter network bandwidth problems that need to limit the use of your shell applications (such as wget, Crul, FTP, SFTP, etc.) to connect to the Internet. How to set the network bandwidth without using complex firewall rules?

Function: Title Code: #!/bin/sh recursive () {for file in $ do subfile= ' ls $2$3/$file ' for SUBSUBF Ile in $subfile do # echo $subsubfile if ["$subsubfile" = = "$2$3/$file"] Then RM-RF $3/$file mv $subsubfile $3/$file else

HBase is a distributed, column-oriented, open-source database derived from a Google paper, BigTable: A distributed storage system of structured data. HBase is an open source implementation of Google BigTable, which leverages Hadoop HDFs as its file

--------------------------------------------------------------- echo "Please Y-to continue"Read ynIf ["$yn" = "y"] | | ["$yn" = "Y"]; Thenecho "Script is running ..."Elseecho "stop!"Fi Note that there are spaces oh------------------------------------

This shell script is used to obtain the MAC address of the intranet host of the 192.168.4.0/24 network segment in bulk#!/bin/bash#Author:Jink#这脚本使用ping和arp命令获取内网主机的MAC地址，查询到的MAC地址写入到文件中myping(){ ping -c2 -w1 -i0.5 $1 &>/dev/null if [ $? -eq 0 ]

Shell Programming I. Introduction to the ProgramProgram程序：算法+数据结构数据结构：数据在计算机中的类型和组织方式算法：处理数据的方式面向过程：以指令为中心，数据服务于指令面向对象：以数据为中心，指令服务于数据计算机：二进制执行Advanced Programming Languages:编译：高级语言->编译器->机器代码->执行解释：高级语言->执行->解释器->机器代码 shellThree major

In the previous section we learned about the Shell's echo command, which we'll learn from the Shell's other output command printf.The printf command mimics the printf () program in the C library.printf is defined by the POSIX standard, so scripting

In daily work, the bash shell has a very frequent time operation. For example, when the shell script sends statistics periodically, it will check whether the scheduled send time is current. Or when you use a file to save some data, a time string is

I use the Mac is when you start a Python port process, even if it is turned off, the background process is still present, the process of initiating the same port, or the error prompt has been occupiedWhen you lsof-i: the port number (linux--(SS-ANPT

1, disk use warning and send mail#!usr/bin/bash#df-th|grep '/$ ' This is the record that gets the memory used#后面两句是获取内存的使用率disk= ' df-th|grep '/$ ' |awk ' {print $ (NF-1)} ' |awk-f '% ' ' {print '} 'Mail_user=natashaIf [$disk-ge];thenecho "' Date

ObjectiveWe have successfully installed the Linux system--centos7, and now follow the super brother to the gate of Linux.So!Start a picture, equip all by dozen ...What the hell is this black one?Using Linux every day, is to open the virtual machine,

It is found that gnome shell 3.4 Is Very dazzling, and it is much easier to use than gnome-Classic. Installation Method: sudo apt-get install gnome-shell After logging out, select gnome to apply the application, instead of "gnome-classic. Install

Linux empty device file and redirection Output/input redirection>>>&> 2 &> 2 <>>&> & 2 File descriptor (file descriptor), which is represented by a number (usually 0-9.Common file descriptors are as follows:Default file descriptor name0 standard

In Bash, you can use the following three methods to process command lines:ParametersEach method has its own application scenario.1. perform direct processing, parse $1, $2,..., $ N in sequence, and perform manual processing respectively;2. getopts

root@bt:~/test# ln --helpUsage: ln [OPTION]... [-T] TARGET LINK_NAME (1st form) or: ln [OPTION]... TARGET (2nd form) or: ln [OPTION]... TARGET... DIRECTORY (3rd form) or: ln [OPTION]... -t DIRECTORY TARGET... (4th

   Shell itself is a program written in C language, which serves as a bridge between users using Linux. Shell is both a command language and a programming language. As a command language, it interactively interprets and executes user-input

The current Code only contains the part used to create a file image and generate a file system. #! /Bin/sh # log = ". /version_make.log "root_path = ". /update_file/network_update "log = ". /update_file/version_make.log "ver_f = ".

The basis of each condition statement is to determine what is true or false. Whether or not you understand the working principle of the script will determine whether you are writing a quality script or a script that you will be proud.The ability of