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The Linux Shell Script Foundation has been divided into several parts, where the content of the control process is immediately finished, this is the last part about here document, where the example is a little bit more complex, we slowly analyze this complex Linux shell script. 6. Here documents When you want to pass a
Write a script:1. Add 10 users user1 to User10, password with user name, but only if the user does not exist to add;#!/bin/bash# forIinch{1..Ten}; Do if!IDUser$i >/dev/NULL; ThenUseradd user$iEcho "user$i"|passwd--stdin user$iElse Echo "User$i exists" fi DoneDelete the above 10 users#!/bin/bash# forIinch{1..Ten}; Do if IDUser$i >/dev/NULL; ThenUserdel-r user$i >/dev/nullEcho "user$i deleted" Else Echo "user$i NOT EXISTS" fi DoneExtension: Adds or deletes a specif
) # #开启虚拟机echo Start VM ...Virsh Start $ >/dev/nullEcho Start VM $ successful!!!;;View) # #显示虚拟机Echo View VM ...Virt-viewer $ >/dev/nullEcho View VM $ successful!!!;;Stop) # #关闭/Stop virtual machineecho Stop VM ...Virsh Destroy $ >/dev/nullEcho VM $ is stopped!!!;;Reset) # #重置虚拟机echo Reset VM ...Virsh Destroy $ >/dev/nullVirsh Undefine $ >/dev/nullRm-fr/var/lib/libvirt/images/$2node.qcow2 # #删除原磁盘快照文件Qemu-img create-f qcow2-b/var/lib/libvirt/images/$2.qcow2/var/lib/libvirt/images/$2node.qcow2 >/
In Linux systems, the two most important files for user account management are/etc/password and/etc/shadow.In the/etc/password file, each line represents an account, but there are many accounts that are system accounts. Like what:Bin, ADM, etc., as well as administrator account root. The rest is for general user accounts.Each line is composed of (to: Split):1 acc
addition to Shebang, the # occupies the absolute beginning of the content, is the comment line, the interpreter ignores the contents of such a line;3. The explanation ignores all blank lines in the script;4. Lots of commands and keywords (if,else,then,do,while,for, ... ）Note: Once the shell script runs in the current shell
]:~/learn$ cat Args.txt | Xargs SH cecho.sh;Arg1 arg2 arg3#Requirement 3, how do I embed parameters in a fixed command line? As shown below:Copy CodeThe code is as follows:[Email protected]:~/learn$ sh cecho.sh-p args1-1-P args1-1#[Email protected]:~/learn$ sh cecho.sh-p args2-1-P args2-1#[Email protected]sli-pc:~/learn$ sh cecho.sh-p args3-1-P args3-1#Solutions for using Xargs:Copy CodeThe code is as follows:[Email protected]:~/learn$ cat Args.txt |
Overview:Overview:This section describes the array of shell scripting in Linux, advanced string processing, advanced variables, and configuring the user's environment.One, function and positional parameter extension1. TheShift command implements the jump in the position parameter, which squeezes the leftmost parameter650) this.width=650; "src=" Http://s1.51cto.co
spaces. If IFS is null, the parameters is joined without intervening separators.oldifs= "$IFS" ifs= "" array= ($result) ifs= "$oldIFS" for I in ${array[@]}; Doecho $idone# Use Facter to get a set of Key-value# Facter output has a newline character, you must replace the newline character with a space# Replace newline characters with spaces to use awk or sed# awk-v rs= "" ' {gsub ("\ n", "");p rint} '# ECHO-E "2 \n1" | Sed ': A; n;$!ba;s/\n//g 'result=$ (facter | awk '/ipaddress/!/ipaddress_lo/{p
updated successfully.Changing password for user bruce03.Passwd:all authentication tokens updated successfully.Changing password for user bruce04.Passwd:all authentication tokens updated successfully.Changing password for user bruce05.Passwd:all authentication tokens updated successfully.Changing password for user bruce06.Passwd:all authentication tokens updated successfully.Changing password for user bruce07.Passwd:all authentication tokens updated successfully.Changing password for user bruce0
No orders found. 128 Invalid exit parameter 128+x Critical error for Linux signal x 130 Command terminated with CTRL + C 255 Exit status code out of bounds Exit Exit command can specify exit status code, but not more than 255, otherwise it will be moduloCode 1-16[Email protected]:/data# cat Demo4 #!/bin/bashdateecho $?whoexit 5[email protected]:/data#./dem
, which is represented as a local variable. such as local temp=1 .Example 3. Array Parameterstest3.sh#!/bin/bash Span class= "hljs-comment" ># trying to pass a array variable function testit {local newarray # use ' local ' define a local variable newarray= (' echo " the NewArray value is ${newarray[*]} "}myarray= (1 , 2 , 3 , 4 , 5 ) echo "the original array is:${ Myarray[*]} " testit $myarray Test:sh test3.shOutput:The original array is:1,2,3,4,5The NewArray value is 1,2,3,4,5Example
value of a running process Renice-n PIDNohup SH executes scripts in the backgroundCtrl Z hangs a foreground processFG Job Number The file foreground runs the BG job number to run the file background/proc DirectoryShell Scripts Scripta shell script is a text file that contains a shell directiveShell and oh ah this supports variables with simple syntax to complete batch workHow
/etc/crontab Add the following code: Here's an example of an hourly 26-minute execution: * * * * * root/home/**/wewang/autobackupmysql_qas.sh If executed at three O ' Day, then: XX 3 * * * root/home/**/wewang/autobackupmysql_qas.sh Case 2:redhat situation. ( that is, the currently used Linux system ) Copy the script you just edited to the appropriate directory [Email protected]***** wewang]# CP autobackupmysql_qas.sh/etc/cron.da
file is a script that is executed when the Linux system startsEdit the Inittab file (use the Vim/etc/inittab command to open the file)Example: Add a statement to the Inittab file to allow the system to execute a shell script file that checks the system disk when it starts checkdisk.shcheckdisk::once:/sbin/checkdisk.sh >/dev/console 2>1 indicates that this command is executed at each runlevel, if it is to b
instruction (displays the exit status of the last command. 0 means no error, any other value indicates an error)$-shows the current options used by the shell, same as the SET command function[email protected] is similar to $*, but can be used as an array--------------------------------------------------------------------------------------------------#!/bin/sh##############Export lang= "ZH_CN. GB18030 "Export JAVA_HOME=/USR/LOCAL/JDKExport path= $JAVA
Lynx 52424.2 Curl Program 52724.2.1 Installing Curl 52724.2.2 Explore Curl 52724.3 using ZSH to process the network 52824.3.1 TCP Module 52824.3.2 client/server mode 52924.3.3 using zsh for C/s programming 53024.4 Summary 533The 25th Chapter uses e-mail 53425.1 Linux e-Mail Basics 53425.1.1 e-mail in Linux 53425.1.2 Mail Delivery Agent 53525.1.3 Mail Delivery Agent 53625.1.4 Mail User Agent 53725.2 setting
sundo Echo ' Today is $var 1 ' donefor var2 in {1..10..2}doecho ' this is $var 2 "Donefor Var3 in $ (SEQ 1 2) Doecho" I had a/an $var 3 "Donefor VAR4 in $ (LS) Doecho" Here's the file $var 4 "doneWhile loop#!/bin/bashi=1while ((I SELECT statementThis SELECT statement to the time the wood has seen, run when you can interact with the user, run the following program to understand. If you don't break it, you're going to die.#!/bin/bashecho "which color do you like?" Select Var1 in red Green Bluedoe
A. Triangle Square exercise1. Print triangles, method one, regular expressions650) this.width=650; "src=" Https://s3.51cto.com/oss/201711/21/ea1ad50480c4e888094441dee06b962f.png "style=" float: none; "Title=" screenshot from 2017-11-21 21-34-44.png "alt=" Ea1ad50480c4e888094441dee06b962f.png "/>Method two, loop nestingI control lineJ Control Printing symbols650) this.width=650; "src=" Https://s3.51cto.com/oss/201711/21/e08401143190fdb2eb60e1ef084e1528.png "style=" float: none; "Title=" screensho
12 methods for linux shell to process text line by line 1. cat $ filename | while read line example: function while_read_line {cat $ filename | while read line do www.2cto.com echo "$ line
Introduction to Shells and scripts The Gnu/linux Shell is an interactive tool that provides users with the means to start programs, manage files on file systems, and manage processes running on Linux systems. At the heart of the shell is the command line
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