Shell

Shell special characters: 1. Wildcard character 2. Piping1. Wildcard characters1.1 asterisk (*): matches any length1.2 Question mark (? ): Matches a length of characters1.3 square brackets ([...] ): matches the character specified in it1.4 Square

1. MakefileThe first thing to know is what Makefile is, Makefile is a directive file, which stores custom commands (which can be created with the help of existing commands), and differs from Makefile in different systems, linux/ In UNIX systems, the

1, there are two common ways to run a shell script:First give executable permission, then enter the directory where the file is located, enter:./name.sh;Run the interpreter and execute the script:/bin/sh name.sh, in which case there can be no #! in

I. The existence and judgment of documents-D to determine if the file exists and whether it is a directory file (the directory is true)-E to determine if the file exists (exists as true)-F to determine if the file exists and is a normal file (the

Conditional Select if statement 选择执行： 注意：if语句可嵌套 单分支 if 判断条件;then 条件为真的分支代码 fi 双分支 if 判断条件; then 条件为真的分支代码 else条件为假的分支代码 fi 多分支 if 判断条件1; then 条件为真的分支代码 elif 判断条件2; then 条件为真的分支代码 elif 判断条件3; then

In shell scripts, there are some common special variable representations that need to be known.Here are some of the frequently used special variable representations:$ Current PIN name$ ... Parameters of the incoming script or function (greater than 1

1. Arithmetic operators2. Relational operators3. Boolean operator4. String operator5. FILE-related operatorsArithmetic operatorsThe bash shell does not provide any mechanism to perform simple arithmetic operations, but we can use some other programs,

Instance one, compare two integer sizes#!/bin/Bash while true DoRead-P"Please input the int nums:"a BExpr$a + $b +0>/dev/NULL 2>&1 #判断是否为整数 if[$?-eq0];Then #返回值是否为0 if[$a-gt $b]; Then Echo "$a > $b"Exit0 elif[$a-lt $b];

Shell scripts are especially important in the daily operations, and often we write shel scripts that involve a lot of privacy information, including passwords, which requires the shell script to be encrypted and the results to be executed. The

Shell: 1, local variables: variables available only in the current shell, 2, Environment variables: variables available for the current Shell's child processes 3, Shell variables: some shell Set the special variables, such as: $ $, $ ... These

1,linux The difference between the shell regular expression * and the + numberExample Memory:[email protected] data]# Touch test.txt[Email protected] data]# cat>>test.txt> Gooood> Goood> Good> God> GD> EOF* indicates repeating the preceding

1. Method 1[CPP]View PlainCopy #!/bin/bash For ((i=1;i Do Echo $i Done Save As For1.shDirect SH for1.shWill error:The Syntax Error:bad for loop variable workaround code is not a mistake for standard bash, because

Symbol Meaning ; Command delimiter # configuration file comments; Root user command terminal prompt ~ Home Directory CD ~ - Previous Path CD-Su-linux Switching user

First, Shell Script Foundation1. First ScriptVim first.shThere are three ways to execute scripts, respectively:./first.sh (need to have executable permissions)SH first.sh  . first.sh(or source first.sh)2. Redirects and Pipe breaks1) redirected

#!/bin/bashRead-p "Input a dight:"Echo $REPLYDate= ' Date 'echo "DATE is ${date}"Users= ' Who |wc-l 'echo "LOGIN in User is ${users}"up= ' Date;uptime 'echo "Uptime is ${up}"#echo "HELLO world!"#echo "What's Your Name"#read person#echo "HELLO

linux-Shell core and shell relationshipThe kernel is in the shell, interacting with the shell (command line) through the shell#####################################################################################################Shell Viewwhich $SHELL/

1. Basic usage of shell variables and usage of common symbols( 1 ) Change the main prompt to the user's home directory namePS1 value restores default values after re-login.(2) the string DOS file c:>\ $student \* assigning values to variables x ,

2. Correct method1) Use LetVar=1Let "Var+=1"Echo $varThe output is 2, no tragedy this time.Attention:A) I tested let almost support all operators, see an article on the internet said "let does not support + + 、--and comma, (,)", but after I test the

Experiment FourBasic usage of 1.shell variables and usage of common symbols(1) Change the main prompt to the user's home directory name(2) Assign the string dos file c:> $student * to the variable x and display it(3) In the shell command Terminal

Title Link: https://nanti.jisuanke.com/t/27644Main topic:Problem Solving Ideas:Code:1#include 2 #defineLC (a) (a3 #defineRC (A) (a4 #defineMID (A, B) ((A+B) >>1)5 #defineFin (name) freopen (name, "R", stdin)6 #defineFout (name) freopen (name, "W",