Shell

#!/bin/bash#echo "1.$12.$23.$3"If ["$" = "+"]ThenRes= ' expr $ + $ 'echo ">>the result is: $RES"elif ["$" = "-"]ThenRes= ' expr $-$ 'echo ">>the result is: $RES" #这里说明下, using "x" instead of "*" #是因为在命令行输入 *,shell parsing problem, #* cannot be

Question: How does the shell judge a filename to start with a character ~ Solve: #var = "cn get the length of me" #$1:parameter 1 to judge the name of the file Var=$1 Iscn=false # ${var:0:2} takes the Var substring from the No. 0 character and

On Windows with notepadd++ edit a shell script, die or die, back to Linux, edit, or have this \ r, search the next, is this: http://bluemood.blog.51cto.com/1142811/1030925 ‘ because the shell processed the character file in Windows, the string

There are many kinds of arithmetic operations in the shell, such as a=1,b=2, so how to calculate the value of A+b? Can not simply $a+ $B, if this operation, the result is 1+2, obviously not the result we want, the result is 3, we have a few methods:

Example No. 2As a shell writer, often face the problem of inconsistent data format, the data standard session output is a need to solve the problem, this example takes MySQL time as an example, the script enters the month, the day, the year three

This example takes the class C address as an example, if it is a Class A or class B address, the script can be modified slightlyIpaddr= '/usr/sbin/ip a | grep $1 | grep inet | awk  ' {print  $2} ' netmask= ' echo ${ipaddr} | awk -f  '/'   ' {print $2

ifMulti-branch statement practice#!/bin/bashread-p " Please enter 100 m running seconds: "IIf [$i-lt] && [$i-GT 0]Thenecho " Enter the final "read-p " enter male and female "aif [$a = male]Thenecho " into the men's group "elif [$a = female]Thenecho "

Share a recently written shell script that enables you to back up the production line files and rollback operations by the file directory structure of the published package.1#!/bin/SH2Path="/home/www/site1"3pub= $path"/release/pub/mboxii/trunk"#发布目录4

Both exec and source belong to the Bash Internal command (builtins commands), where you can view all the internal command information by entering man exec or man source under bash.The bash shell commands are divided into two categories: external

First, killandclean.sh#!/bin/bashpid= ($ (ps-ef | grep tomcat | egrep-v grep | awk ' {print $} ')) length=${#pid [*]}if [$length-gt 0] thenfor i in $pid does ' kill-9 $i ' done with echo ' kill over ... '

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

Lab Environment:System: centos7-3.10.0-x86_64Testing Services: apache-tomcat-9.0.7Experimental reasons:Because the current environment for the Java test environment, so did not monitor, but recently found that the service is automatically down, and

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];

Three ways the shell command executes continuously:1, command 1; command 2; command 3Executes the command sequentially, regardless of whether the previous command executed successfully.2. Command 1 && Command 2 && command 3The next command is not

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

#通配符 {} * []?1.1 The difference between quotation marks and unquoted 1:[[email protected] ~]# touch a B[email protected] ~]# LLTotal 0-rw-r--r--. 1 root root 0 June 16:25 a-rw-r--r--. 1 root root 0 June 16:25 b[[email protected] ~]# touch "a

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/

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",