Shell

Tput commandtputYou can change terminal features, such as moving or changing the cursor, changing text properties, clearing specific areas of the terminal screen, and so on.Cursor PropertiesIn a shell script or command line, you can change the

The file name of the shell script usually ends in. sh, or in other formats, such as. txt or even without a suffix. The #!/bin/bash of the first line of the script represents the parser that specifies when the script executes.#!/bin/bash# file name:

RegularGrepMatch, and can display the colorfilter, display line numbers, case sensitiveGREP-V ReverseTake 2 lines, next 2 lines, two rows above and belowLines that begin with #Do not print the beginning of the #, for example, when looking at the

(1) SED effectSED is a non-interactive text editor, and the Contrast VI (VIM) is an interactive editor(2) SED syntaxsed [-option] [command] FilesComments:SED tool default processing text, text content output screen has been modified, but the

1.shell (Bourne Agin Shell) is a command parser that provides interaction between the user and the machine, as well as zsh, Ksh2. Where are the orders that we have knocked on? In the. bash_history file in your home directory, you can save up to 1000

1. Judge whether the number entered by the user is a positive integer.#!/bin/bash#判断用户输入的参数是否为正整数Read-p "Please input a digit:" intif [["$int" =~ (^[0-9]*[1-9][0-9]*$)]];thenecho "This digit is positive integer"Elseecho "This digit was not positive

1.1. usage of the Cut command in the shellThe first usage is similar to awk, as shown in awk below :Cat/etc/passwd|awk-f: ' {print $1,$5} 'Cut-d: The colon after-F 1,5/etc/passwd/-d indicates the delimiter between the fields, and-f indicates which

1.1. The data type of the shellthe data type of the shell is a dynamic data type. That is, it does not need to be defined beforehand and can be used directly. The type can be changed at any time during use. For example , awk {' print '}/opt/test.txt

1.1.various Judgments1.1.1.string JudgmentsSTR1 = str2 When two strings have the same content, length is trueStr1! = str2 true when string str1 and str2 are not equal-N str1 True when the length of the string is greater than 0 ( string non-null )-Z

first, the circulation　　1. Indefinite circulation　　There are two kinds of forms: while [Condition] state in parentheses is the beginning of the loop of the judgment do done do is the end of the loop　　When the condition condition is established,

first, how to debug　1. Parameters through the SH command:SH [-NVX] Scripts. SH options and Parameters:-N: Do not execute script, query syntax only;-V: Before executing sccript, output the contents of scripts to the screen;-x: script to be used The

The shell in Linux is an outer-layer protection tool for the Linux kernel and is responsible for completing the interaction between the user and the kernel.A command is a text stream in which a user issues a control request to the system kernel and

Shell Pass ParametersWe can pass parameters to the script when executing the Shell script, and the format of the parameters obtained in the script is:$n. n represents a number, 1 is the first argument to execute the script, 2 is the second argument

The set command functions primarily to display shell variables that already exist in the system, and to set new variable values for shell variables. The set command is not able to define a new shell variable. If you want to define a new variable,

Shell script:A text file that contains some commands or declarations and conforms to a certain formatFormat requirements: First line shebang mechanism#!/bin/bash#!/usr/bin/python#!/usr/bin/perlThe purpose of the shell script is:? Automation common

I wrote a shell script today, hoping to simplify the problem of login proxy server, but when script was written, it found that the environment variables were not obtained as expected.In order to make everyone understand, post the script content for

First, the basic regular expression1. Regular expression: The regular expression is the string used to match the symbol condition in the file, and the Regex contains the matchinggrep, awk, sed, and other commands can support regular expressions.2.

The file name of the shell itself$1~ $n Each parameter value added to the shell. $ $ is the 1th parameter, and the $ = is the 2nd parameter ...$$ the shell itself PID (ProcessID)$! PID of the Shell's last running background process$? End code of the

　　This sort algorithm is very powerful, I personally like this algorithm, but the time complexity of the algorithm is difficult to calculate. The algorithm's choice of increments (here also called step) also needs to be noted, remembering only the

Lite version:Definition: your_name=123 ps:= symbol can not have space around! Use: ${your_name}, you can use the variable alone without {}Read only: readonly your_name PS: not deleted after set to read-onlyDelete: unset your_nameQuotation marks: