bash getopts

Under the AIX system, the default is not to install bash environment, for the regular operation of the maintenance personnel, very inconvenient, so let's install bash.1. Confirm if bash is installed on the systemMethod 1: Bash between commands, if prompted without this command is not installedMethod 2:rpm-qa|grep Bash2

Sequential execution: Default rule, execution of each statement by clauseSelect execution: Branch, condition judgment, and qualified branch to execute;Loop execution: The same piece of code is repeatedly executed for a finite number of times, so the loop must have an exit condition or it will fall into a dead loop.Program code: statement and expression compositionControl statements:Bash loop control statement: for while untilFor loop:for var_name in list; DoStatement 1Statement 2...DoneLoop add

Linux Bash getting started learning notes, linuxbash learning notes It is very useful to learn shell programming well. You can use shell scripts to easily complete interesting work. Address: http://www.cnblogs.com/yhLinux/p/4047516.html Bash instanceBy Daniel Robbins (drobbins@gentoo.org), President and CEO, Gentoo Technologies, Inc. This article is divided into three parts, starting from a simple introdu

Iii. Command HistoryBash has absorbed a lot of essence from the Korn shell and the C shell, one of which formally holds the feature of a cached copy of the executed command, which we call the "command history" feature.Why should we use the command history feature?After each user login succeeds, especially after login with file interface such as bash, all operations are implemented by executing commands, it is inevitable to repeat a command, if each co

The first Bo begins with the word, according to the "second analogy, when looking, use this setting will quickly find the answer, when you find the word to match", don't forget to enter set Incsearchset hlsearchset IC "ignorecase" encoded set Encoding=utf-8set Fileencodings=utf-8,gbk,gb18030,big5set Termencoding=utf-8 " You can use the mouse anywhere in buffer (similar to double-clicking the mouse in the workspace in office) set Mouse=aset mouse=vset selection=exclusiveset Selectmode=mouse,key

Command editing ability (history):One of the great features of Bash is that "he can remember the commands he used!" "This is a really great feature!" Because I just press "up and down" in the command column to find the front/rear input command! In many distribution, the default command memory function can reach 1000! In other words, almost all of the commands you have issued have been recorded.Where are all the commands recorded? In your home director

Command editing ability (history):One of the great features of Bash is that "he can remember the commands he used!""This is a really great feature!" Because I just have to press the "up and Down" button in the command line to find the front/rear input command!And in very many distribution. The default command memory function can reach 1000! In other words, almost all of the commands you've issued have been recorded.Where are all the commands recorded?

The 1.bash shell is the default shell command interpreter for most Linux distributions, but a recent burst of bash shell has been exploited.2. If bash is the default system shell, network attackers can attack servers and other Unix and Linux devices by sending Web requests, secure shells, Telnet sessions, or other programs that use

Problems encountered in Bash programming:First, it is recommended that you write bash under Linux, and if you want to write bash with Windows, you should pay special attention to several issues:First: Coding problems, encoded with utf-8,Second: line break problem, Windows is the end of carriage return (CRLF), Linux is the end of line break (LF)Third: Use Utf-8 wi

I had a problem learning Linux today. #!/bin/sh # test.sh username= ' HCBBT ' echo ' My name is ${username}. Call me ${username:0:1}-chan. " This script runs directly to the Times wrong:/test.sh:5:./test.sh:bad substitution.Toss, found that the first line of the interpreter changed to/bin/bash is no problem. So I checked the difference between/bin/sh and/bin/bash, using: Intercept the string is not POSI

Tags: bash first knowledge1.Linux System Terminal OverviewServer Terminal switch: Ctrl + Alt + F1 ... F6Virtual Machine Terminal switch: Ctrl +shift +alt +f1 ... F6The virtual terminal is generated by the mingetty program//物理机执行为本地终端[[emailprotected] ~]# tty/dev/tty1//通过网络使用模拟终端远程连接Linux, 日常运维中就是这种方式。[[emailprotected] ~]# tty/dev/pts/12.Linux System Bash ManagementIn a nutshell, the shell is the user interf

Bash remote parsing command execution vulnerability Test Method Since yesterday, the BASH remote command execution vulnerability from a vast ocean of Australia has boiling the entire FreeBuf. Everyone is talking about it, "The Heart of the Internet is bleeding again, how can I test my website? The following script $ env x=‘() { :;}; echo vulnerable' bash -c "ec

IntroducedUnderstand The boot sequence of Linux also helps to understand this content, loading the user environment is the last step of Linux boot. Different shells use different configuration files :　Bash (. Profile), Ksh (. Profiles), CSH (. Login). The Bash Shell is designed to be compatible with SH, ksh, which is checked in the user's home directory in turn . Bash_profile,. Bash_login,. profile exists a

Shell on the bashunix-like system, which allows users to input and execute commands in the Unix-like system. Generally, the connection is implemented through SSH or Telent. In addition, the Web server can also be used as an interpreter for CGI scripts. The Unix-like system has multiple shells, but it is the default shell. Bash vulnerability Description: Bash processes the strings defined by the function

This article is the Reading Notes of customizing your environment, chapter 3 of learning the bash shell 3rd edition. Setting up a good user environment is crucial for our development. This section describes four aspects: special files, aliases, options, and parameters. Special files There are several special files in the user directory.Ls- To view these hidden system files .. Bash_profile is only an important file and is often used to set the user en

This article is the second chapter of "learning the bash shell" 3rd edition, command-line editing, Reading Notes. But we will not limit this. In general, I just try to press it directly. If an error occurs, use the cursor and arrow on the left or right to modify the image, or use the upper/lower cursor to directly use the previous command or previous command to modify the image. That's all. I use VI and almost do not use Emacs. The author of this book

CentOS Grub, BASH fault, Solution Introduction: Two common faults of Grub: Grub. conf file loss and MBR damage (no matter what the recovery is, back up the file first) 1. Grub. conf file loss Shell> rm-rf/boot/grub. conf # delete files, simulate faults, shell> reboot # Faults: GNU GRUB verstion 0.97 (634k lower / 1046400k upper memory )[ Minimal BASH-like line editing is supported. For the first word, TAB l

CentOS Grub, BASH fault, solution, centosbash Introduction: Two common faults of Grub: Grub. conf file loss and MBR damage (no matter what the recovery is, back up the file first) 1. Grub. conf file loss Shell> rm-rf/boot/grub. conf # delete files, simulate faults, shell> reboot # Faults: GNU GRUB verstion 0.97 (634k lower / 1046400k upper memory )[ Minimal BASH-like line editing is supported. For the first

Fixed the GRUB error of "providing pocket BASH... like line editing" in Linux. These two days I installed Elementary OS and Windows, and encountered a Grub error at startup. The command line displays the following information: Minimal BASH like line editing is supported. For the first word, TAB lists possible command completions. anywhere else TAB lists possible device or file completions. Provides a pocket

Fun Bash Script: select the structure if 3rd articles Almost all programming languages have the concept of process control, that is, order structure, selection structure and loop structure. The selected structure is also called the branch structure, such asIfAndSwitchStatement.If condition I have already discussed the use of the test Expression and Its Simplified [] Operator. These judgment statements can be used as conditions for the if structure. In