bash amplifier

Transferred from: Http://blog.chinaunix.net/u/8681/showart.php? Id = 1145851 I bet you are reading this article. more than 99% of the possibility is that you are wrong about this problem, or at least there is a deviation. I believe that this is a broad mistake in the Education Law, that is, to tell everyone:If [condition]Then...Fi This is the "Syntax" of the Condition Statement in bash ". Anyone, or almost anyone, will naturally think that [and] are

Some bash scripts are not properly written. They are not written at the beginning of the file #!, But it can be executed directly. However, if you look at the kernel code, the start of the shell script's loading function will be determined. If not #! Then an error is returned:Static int load_script (struct linux_binprm * bprm, struct pt_regs * regs){...If (bprm-> Buf [0]! = '#') | (Bprm-> Buf [1]! = '! ') | (Bprm-> sh_bang ))Return-enoexec;...}Why don

}Remove the part of value that matches pattern. The condition is that the beginning of value matches pattern.The difference between # And # Is that one is the shortest matching mode and the other is the longest matching mode.(_Cool.gif src = "/uploadfiles/newsphoto/con_cool.gif" border = 0 >$ {Value % pattern}$ {Value % pattern}Similar to (7), except that the value is matched from the end of pattern. The difference between % and % is the same as that between # And #.(9) $ {value/pattern/string}$

Bash Getopts-Allow your script to support command line parameters In the past, I always wanted to know how to create command line parameters for my Bash script. After searching, I found two functions that can solve this problem: the getopt function and the getopts function. I have no intention of arguing which function is better. Getopts is a shell built-in command, and it seems easier to implement this fun

Getopt/getopts: command line option/parameter processing in Bash 0. When writing a program, you must always process command line parameters. This article describes the command line Processing Method in Bash. Options and parameters: for example, the next command line: [vb]. /test. sh-f config. conf-v -- prefix =/home we call-f as the option. It requires a parameter, that is, config. conf,-v is also an option

Like other shells in Linux, Bourne Again shell is not only an excellent command-line SHell, but also a scripting language. Shell scripting allows you to take full advantage of shell functions and automate multiple tasks that require many commands. There are many shell programs on your Linux machine. If you are interested in learning how they work, or modifying them, the basic element is that you must understand bash syntax and semantics. In addition,

1. Get the bash Source: $ Wget-C http://ftp.gnu.org/gnu/bash/bash-4.1.tar.gz $ Tar zxvf bash-4.1.tar.gz 2. Download the arm toolkit, e.g. sourceryG ++ lite 2008q1-126Arm GNU/Linux $ Wget-C Http://www.codesourcery.com/sgpp/lite/arm/portal/package2549/public/arm-none-linux-gnueabi/arm-2008q1-126-arm-none-lin

Linux official built-in bash recently found a very serious security vulnerability, hackers can use the bash to fully control the target system and launch attacks, in order to avoid your Linux server affected, we recommend that you complete the bug fix as soon as possible.The following is a small series for everyone to attach the most common Linux kernel CentOS and Ubuntu Server Repair

Linux official built-in bash recently found a very serious security vulnerability, hackers can use the bash to fully control the target system and launch attacks, in order to avoid your Linux server affected, we recommend that you complete the bug fix as soon as possible.The following is a small series for everyone to attach the most common Linux kernel CentOS and Ubuntu Server Repair

What is a shell?The shell typically represents two levels of meaning, one is the command interpreter, such as bash, and the other is the shell script. In this section we stand on the command interpreter's point of view to illustrate the shellCommand interpreter shell development history, Sh-csh-ksh-tcsh-bash, let's start with the command interpreter BASH.Priority of TWO commandsThe commands are divided into

Always thought that in the shell script # is to represent the annotation function, also at the beginning of the script #!/bin/sh also just tell the user this is a shell script, and recently checked the next, only to find that this is not the meaning, share the following article.Transferred from: http://www.cnblogs.com/EasonJim/p/6850319.htmlFirst, meaning#!/bin/sh means that this script uses /bin/sh to interpret execution,#! is a special identifier followed by the path to the shell that interpre

Bash is the Linux default shell, and Han O Sinox is also installed, although Sinox does not use bash by default, but the user may be compromised by a vulnerability once it is used, so it must be repaired quickly. Although Sinox uses FreeBSD's ports, FreeBSD has been upgraded to the latest software management Pkg,ports is being eliminated, to be directly updated via PORTSNAP to the latest ports and then inst

Now for the servlet listener listener, it's a server-side program that implements the Javax.servlet.ServletContextListener interface, and it's also started with web apps Starts, initializes only once, and destroys with the Web application stopped.

Directory Part 1. Warm up Why use shell programming? Start with a sha-bang (Sha-bang refers #!) Call a script Preliminary exercises Part 2. Basics Special characters Introduction to variables and parameters Variable replacement Variable assignment Bash variables are of no type. Special variable types References (translation may be incorrect, especially quotation marks) Reference variable Escape (/) Ex