Shell

; for example[Email protected] ~]# date;dd if=/dev/zero of=/home/1 bs=1k count=10240;date # #统计dd命令消耗时间, where/dev/ Zero empty file Tue June 15:15:02 CST 201610240+0 Records in10240+0 records out10485760 bytes (ten MB) copied, 0.0224696 s, 467 M

Michael Stutz, author of the Linux Cookbook, has summed up 10 good habits with his many years of experience in using UNIX, and personally believes that it is really useful, and is summarized below to share with you.1. Create a hierarchy directory:

$*[Email protected]DifferenceThe shift parameter moves forward one bit, moving the position variable.$?$n$#$$!$$#!/bin/shPidpath=/tmp/p.pidIf [-F "$pidpath"]ThenKILL-USR2 ' Cat $pidpath '/dev/null 2>&1Rm-f $pidpathFiecho $$ > $pidpathSleep 300One of

Shell ArrayCommand_list= ([add]= ' Add '[del]= ' Delete '[edit]= ' Modify '[query]= ' query ')Get index: ${!command_list[*]}, according to the index submission value, perform the corresponding operation.Get length: ${#command_list [*]}, traversing

Thank you for the 36,000 sectionCommon Shell Categories: BASH: is the GNU Bourne Again Shell, which is the default shell on the GNU operating system C Shell: The BSD version of Sun's shell Look at where the shell is on the

Overview What is a shell?The shell acts as an interface between the user and the Linux system, allowing the user to enter commands that need to be executed to the operating system. This is much like the command prompt for Windows, but the strong is

*-----Wildcard (multi-bit)?-----wildcard character (one bit)#-----Comment (Explanatory Note)\-----caret (\ #1. txt, let #1.txt become a file name, so that the special symbol behind the loss of meaning)|-----Give the result of one command to another

Tag: TR WC split cutCut interceptCut-d:-f+ number + file to take the first paragraph of the file, with a comma between multiple numbersCut-c intercept the first few characters (3-5 3 to 5)Sort sorts-T delimiter-U to repeat-N Sort by number-K

Escape characters:650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M02/82/B1/wKioL1dekCOAJOxMAADJVCjDcdk147.png "title=" QQ picture 20160613180543.png "style=" Float:none; "alt=" Wkiol1dekcoajoxmaadjvcjdcdk147.png "/>When parsing text, double

Basic format:Test expressionExpression constructed for the test command.Here expression is any valid expression that the test command can understand, and the simplified format will be the most common format that the reader may aiiowed seereturn

#!/bin/bashName="Matto" #变量名和等号之间不能有空格 #name="Blog4matto" #重定义name变量 #readonly name #设置name为只读变量 # unset name #删除变量, you cannot delete a read-only variable #${name}

1. Requirements backgroundFor large companies, there must be a site or configuration file updates from time to time, and the use of the machine is certainly a lot of units, less than a few, more than dozens of or even hundreds of sets. Therefore,

#输入输出重定向: Unix gets input from stdin by default, stdout output, input device is keyboard, output device is terminal#输出重定向: The clear output can be not only the monitor, but also the transfer to the file, which is called the output

I. Shell BasicsCat/etc/shells the shell that the current operating system can useWhat is a shell?A text file that implements a function that has permission to executeCommand-line InterpreterBuilt-in commands (commands provided internally by the

#!/bin/bashSource/etc/profileSOURCE ~/.bash_profile##################################00 * * */bin/bash/utxt/soft/tools/rm_oracle.sh >>/utxt/soft/tools/rm_oracle.log 2>&1#################################lyd_rm_dt= ' date-d '-5 day "+%y%m%d"flow_rm_dt=

1, variable var from npos∈[0, Length-1] bit start, from left-to-right intercept num characters:　　　　${var:npos:num}Summary: If NPOs If NPOs > Length (Var)-1 Then the result is an empty string;If the character does not actually meet the NUM bit, it is

1.shell Introduction The shell is a special-function program that provides an interface for users to interact with the kernel. It is used to receive commands entered by the user and send it to the kernel for execution. The shell is an

Use directly after declaring variables in the shell:#！ /bin/bashNa=zhagnsanag=11Echo ' $na is $ag years old 'Output: $na is $ag years oldecho "$na is $ag years-old"Output: Zhagnsan is one years oldTherefore, use "" in shell scripts to output

1) Multithreading Overview2) Multithreaded script content3) Multithreaded script execution time4) Single Thread script content5) Single Thread script execution time"Multithreading Overview"# multithreading refers to executing tasks concurrently

#数组: Bash supports only one-dimensional arrays, starting with subscript 0.#定义数组: Array_name= (value0 value1 value2), as follows1 array_name=(2value03value14value2 5 )#还可以单独定义数组的各个分量, a continuous subscript may not be used, and the subscript range