linux shell scripting cookbook

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

] ~]# Expr 2 * 3expr:syntax errorSecond, let command[[email protected] ~]# let A=2+3[[email protected] ~]# echo $a 5[[email protected] ~]# let A=2-3[[email protected] ~]# Echo $a -1[[email protected] ~]# let A=2*3[[email protected] ~]# echo $a 6[[email protected] ~]# let A=2/3[[email protected] ~]# echo $a 0[[email protected] ~]# b=4[[email protected] ~]# c=2[[email protected] ~]# let a= $b/$c [[email protected] ~]# Echo $a 2When using let, it is generally necessary to assign them to a variable

Tags: access CHM shell programming intercept help command define variable exp variable define current directoryFirst, prefaceThe shell is a program written in C that is a bridge for users to use Linux. The shell is both a command language and a programming language.A Shell i

Shell Scripting Learning GuideThe following eight points can not be said to be your shell Scripting Learning Guide de all, at least let you write a reliable shell script.1. Specify bashThe first line of the shell script, what shou

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

What is a shell script, first of all it is a script, and not as a formal programming language, so to speak is that the shell script is a collection of commands.All custom scripting recommendations are placed in the/usr/local/sbin/directory, and the benefits are easy to manage and maintain, and facilitate later handover to your replacement administrator.The struct

Create a script There are many different shells in Linux, but usually we use Bash (Bourne again shell) for Shell programming because bash is free and easy to use. So the script I've provided in this article is all about using bash (but in most cases these scripts can also be run in Bash's eldest sister, Bourne Shell).

Tags: now continuegnu file copy border system mina Process Control terminal Create a scriptThere are many different shells in Linux, but usually we use Bash (Bourne again shell) for Shell programming because bash is free and easy to use. So the script I've provided in this article is all about using bash (but in most cases these scripts can also be run in Bash's

Try to make your work more efficient, write scripts, and use scripts, often with less effort. So, take some time today to learn about shell scripting.--------------ahead of the high-energy warning, this article is written slightly entertain, if you have to look uncomfortable, please go to the top right corner----------------------The shell has two ways of executi

What is Bash shell script programming?A: There are multiple shells in Linux, and the default shell for CentOS and Redhat is the bash shell. As for shell scripts, this is a bit like (. bat file) for batch files inside the Windows operating system. I wonder if you remember the

Shell Scripting Learning The shell is the command parser that converts the user-entered instruction into a program that the appropriate machine can run.The shell is a program that acts as an interface between a user and a Linux system, allowing the user to enter commands to

② under Linux sh equals bash,#! is also called magic number, when executing a bash script, the kernel determines which program to use to interpret the contents of the script., this line must be the first line at the top of the script, or a comment if it is not the first lineCentos. and Redhat Linux The default shell is bash④ If you do not specify an interpreter a

two different concepts. For the sake of simplicity, the "shell programming" that appears in this article refers to Shell scripting, not the development of the shell itself (such as Windows Explorer extension development).EnvironmentShell programming is like Java and PHP programming, as long as there is a text editor t

=/var/Log4Root_uid=0# When $uid is 0, the user has the root user's permission5 #要使用root用户来运行6 if["$UID"-ne"$ROOT _uid"]7 Then8Echo"must is root to run this script."9Exit1Ten fi OneCD $LOG _dir | |{#如果cd没有执行成功就执行大括号中的内容 AEcho"cannot change to Nessarg directory">2 -Exit1 - } thecat/dev/NULL>Messages -Echo"Logs cleaned up" -Exit0 -#退出之前0表示成功, returning 1 means failureThree ways to empty a log1 echo >test.log #输入空的内容 2 >test.log3 cat/dev/null > test.log #查看黑洞, redirect black hole to file 4 app: Kee

Recent work requires the use of the hard disk shell script Automation partition and mount operation, Google has some information, the following is a summary.If the hard disk is not partitioned (logical partition or extended partition, about the concept of the two, self-Google), we will not be able to use the hard disk to read and write. We need to take the following three steps to use a hard drive: Partition the hard drive; Format the par

Tags: scripting shell OracleCopy the daily EXPDP export file of an Oracle database to a remote server using shell scriptingZhao Full Text Network name: GuestartWe have a production environment Oracle database, although the daily Rman backup, but also overwhelmed by the developer go out said to restore a few days before the table data into the production environme

Shell script is similar to batch processing under Windows/dos, that is, the use of various commands pre-placed into a file, convenient one-time execution of a program file, mainly for the convenience of administrator settings or management. The advantage of scripting languages over Perl and Python is that it handles the underlying business because there are a lot of Lin