linux scripting basics

Basics of Linux Shell scripting here we first talk about the shell of the basic syntax, the beginning, comments, variables and environment variables, to do a basic introduction, although not related to specific things, but lay the foundation is to learn easily after the premise. 1. Linux

] ~]# vim/root/foo.sh#!/bin/bashIf ["$" = "Redhat"]Thenecho "Fedora"elif ["$" = "Fedora"]Thenecho "Redhat"Elseecho "/root/foo.sh Redhat|fedora" >2Fi2) Add x Execute Permissions[Email protected] ~]# chmod +x/root/foo.shStep two: Test foo.sh judgment Script1) test conditions that provide the correct parameters[Email protected] ~]#/root/foo.sh redhat Fedora[Email protected] ~]#/root/foo.sh Fedora Redhat2) test to provide unexpected parameters[Email protected] ~]#/root/foo.sh Ubuntu/root/foo.sh Redh

command. You can use Echo to print any variable value in any place where you suspect it is wrong. That's why most shell programmers spend 80% of their time debugging programs. of the Shell programThe advantage is that there is no need to recompile, and it does not take much time to insert an echo command.The shell also has a real debug mode. If there is an error in the script "Strangescript", you can debug it this way: Sh-x Strangescript This executes the script and displays the values of all v

results of "mail.jpg tux.jpg".quotation marks (single and double quotation marks) prevent this wildcard extension: #!/bin/shecho "*.jpg" Echo ' *.jpg ' This will print "*.jpg" two times.Single quotes are more restrictive. It prevents any variable expansion. Double quotes prevent wildcard expansion but allow variable expansion. #!/bin/shecho $SHELLecho "$SHELL" Echo ' $SHELL ' The result of the operation is: /bin/bash/bin/bash$shell Finally, there is a way to prevent this extension by using the

script requires a user name list file as a parameter2) If no parameters are provided, this script should give a hintUsage:/root/batchusers, exit and return the corresponding value3) If a nonexistent file is provided, this script should give aShow Input file not found, exit and return the corresponding value4) New User login Shell is/bin/false, no need to set password5) User list test file:Http://classroom/pub/materials/userlist# wgethttp://classroom/pub/materials/userlist[Email protected]/]# vi

1. Linux Scripting Basics1.1 Basic Introduction to grammar1.1.1 StartThe program must start with the following line (must be placed on the first line of the file):#!/bin/shThe symbolic #! is used to tell the system that the parameters behind it are the programs used to execute the file. In this example we use/BIN/SH to execute the program.When you edit a good script, you must also make it executable if you

it into a string$# number of parameters after output script[email protected] references all parameters after the script, but one reference$? Output previous command execution status return codeNumeric operationsLet VAR=ARG1+-*/%ARG2var=[$a + $b]var=$ (($a + $b))var=$ (expr ar1 ar2 ...)Logical operations | | Or! Non -Pstree Show Process TreeExport displays all of the current environment variablesUnset the variables that were set before the undoReadOnly setting read-only variablesDeclare-R Set re

Please follow me to learn some of the basics of using scripting languages (mainly VBScript) in ASP. Before you begin to learn the scripting language, you should understand some simple concepts--variables, processes. A variable is a named storage location in the computer's memory that contains data such as numbers or strings, which makes it easy for users to unde

Starting from the game scripting language, this article analyzes the script basics set up by Mono and the script language mono.0x00 Preface In my daily work, I occasionally encounter the following question: "Why have game scripts become indispensable in current game development ?". So this week I wrote an article about the game script and analyzed why the game script appeared, and what script base does mono

Reprinted from: http://www.92csz.com/study/linux/12.htm The basics before you learn Shell scriptingA shell script is essential for everyday Linux system management, and if you don't write a shell script, you're not a qualified administrator. At present, many organizations in the recruitment of Linux system administrato

files under/var/logPut all the commands in one file and build up the script, here is the simplest command to stack up the script, empty the log script.Cd /var/logCat /dev/null > messagesEcho “Logs cleaned up.”Expand: Three ways to empty logs and file contents[[emailprotected] ~]# echo >test.log [[emailprotected] ~]# >test.log [[emailprotected] ~]# cat /dev/null >test.logScenario: Preserve files and empty content.Two Shell language and category Introduction 1.1 Types of

Simonsu Blog Comment Wall Reader Wall Link About The SH scripting syntax in LinuxPlaying Linux all know the convenience of SH script, but how to write sh script is a novice and rookie problem like me. It is one thing to be able to write, and not to know is another. Holding a good study, the spirit of day up, we have time to see it, no harm. Here's a copy of a large section of t

article, after receiving the strong support of Mr. Hongbin of Chinabyte Network College, you will be able to see this article. The author earnestly hopes that through this article for the vast number of WEB developers and enthusiasts to provide convenience, to enable everyone to participate in the study and exchange of ASP, in order to cover the needs of readers at different levels the author decided to start from the most basic scripting language,

article, after receiving the strong support of Mr. Hongbin of Chinabyte Network College, you will be able to see this article. The author earnestly hopes that through this article for the vast number of WEB developers and enthusiasts to provide convenience, to enable everyone to participate in the study and exchange of ASP, in order to cover the needs of readers at different levels the author decided to start from the most basic scripting language,

whether the VSFTPD service is running, if it has been run to list its listening address, PID number, otherwise the output hint "VSFTPD service is not available!" ”First install the VSFTPD software, turn on the VSFTPD service (software CD)Then write the script vim chkftpd.sh[Email protected] ~]# chmod +x chkftpd.sh[Email protected] ~]#./chkftpd.shJINGGAO:VSFTPD fuwubukeyong!Set permissions and execute to prompt vsftpd service not availableExecute script again after opening VSFTPD server3. Multi-

Http://classroom/pub/materials/userlist[Email protected]/]# vim/root/batchusers#!/bin/bashIf [$#-eq 0];then//$ #位置变量的数量, when no arguments are provided, the $ #为0, the expression is setEcho ' Usage:/root/batchusers ' >2//output Usage:/root/batchusers >2 into error outputExit 1//Return value 1, prompt for wrong input parameterselif [!-F $];thenEcho ' Input file not found ' >2Exit 2FiFor a in $ (cat $)DoUseradd-s/bin/false $aEcho $a created successfullyDone########################################

First part: Linux command line"Linux command line and Shell Scripting Encyclopedia" chapter I: the first knowledge of Linux shell"Linux command line and Shell Scripting Encyclopedia" chapter II: Into the shell"

seconds, in the shell script of the usual term loop.At this point, you press CTRL +z to pause it, and then enter BG to go back into the background.In the case of multitasking, if you want to move the task to the foreground, FG is followed by the task number and the task number can be obtained using the jobs command.9. >>, 2>, 2>> : The above-mentioned directional symbols > and >> denote the meaning of substitution and addition, then there are two symbols which are 2> and 2>> here. Indicate erro

languages. This begins with what we call the shebang mechanism, and his main function is to tell the system that the file should be executed by the Bash interpreter, followed by the body of the program.The content of the text is what you want to complete, then how to write the text content? The main ideas are as follows: Demand analysis Program Logic Analysis Writing Program Debugging bugs First, let's take a simple script topic as an example:

]shell]#catfun1.sh#/bin/bashread-p "Please enter the network card:" networkip () {ifconfig $network |head-2|tail-1|awk -F ': ' ' {print$2} ' |awk ' {print$1} '}case $network ineth* ) echo "This is the Ethernet NIC," ipaddr= ' ip $network ' echo ' $network IP is: $ IPAddr ";; lo) echo "This is the loopback network card" ipaddr= ' ip $network ' echo "$network IP is: $ipaddr" ;; *) echo "You entered the incorrect, please new input!" ";; EsacExtended Learning:Select is also a kind of loop, it is