Linux Design Guidelines

Computer Architecture:

operator controller memory, memory, address output device input device

Linux kernel Features:

Process Management
Memory management
File system
Network functions
Hardware Drivers
Security Mechanisms

Basic principles of Linux:

1, consisting of small programs with a single purpose; the combination of small programs to complete complex tasks; 2, all documents; 3, to avoid capturing the user interface; 4, the configuration file is saved in plain text format;

Linux Open source license:

GNU: GNU is not Unix, The GNU program, also known as the Slave program, isRichard Stallman publicly launched on September 27, 1983. Its goal is to create a set of completely free operating systems. One of the reasons why Richard Stallman first published the news on the Net.unix-wizards News Group was the article on why the GNU Declaration was launched, and one reason for that was to "recreate the spirit of solidarity that the software community has cooperated in the past year." In order to ensure that GNU software is free to "use, reproduce, modify and distribute", all GNU software has an agreement to grant all rights to anyone without the addition of any restrictions to any other person, the GNU General Public License (GNU LICENSE,GPL). The concept of "anti-copyright" (or copyleft).   GPL: (general public License) and LGPL are two of the GNULicense . A growing number ofFree software (free software) use of the GPL as its authorization statement, if the GPL is not understood at all, it is possible to use the software in violation of the GPL license, I am afraid there is a risk of being sued. Therefore, any company should ensure that it is licensed under LGPL or other GPL variants before using free software. LGPL: LGPL isGnu Lesser general public License (GNU wide Universal Public License) abbreviated form, formerly known as the GNU Library (Common Common license) License (GNU), later renamed as Lesser GPL , that is, the more liberal GPL, the looser degree with whichBsd , Apache ,XFree86  License similar. GPLv1： GPL version 1, the original version, was released in January 1989 to prevent the blocking of free software, which has two main impediments to open source software (one is that the software publisher publishes only the executable binary code and does not publish the specific source code. One is a software publisher who adds restrictive terms to the software license. Therefore, by GPLV1, if you publish executable binaries, you must publish the readable source code at the same time, and you cannot add any restrictive terms when publishing any GPL-based software. GPLv2: Richard Stallman The biggest change in GPLv2 is the addition of the " Freedom or death? ("Liberty or Death") This chapter of the clause, namely Chapter seventh Liberty-or-death Presentation. This chapter states that if a person releases software from the GPL, it also adds mandatory terms to protect and respect some other people's freedom and interests to a certain extent (i.e., in some countries, people can only release software in the form of binary code to protect the copyright of developers who develop software). Then he will have no right to publish the software. GPLv3： of all the changes, the most important four are: 1, 2. Solve the software patent problem; compatibility with other licenses; 3, definition of partition and composition of source code; 4. Resolve Digital Rights Management (DRM) issues.

Linux Two types of Windows:

1.gui:graphic User Interface graphical interface Windows X-window Gnome KDE Xface2.CLI:Command lines Interface command line interface SH Span class= "Apple-tab-span" style= "WHITE-SPACE:PRE;" > bash csh ksh zsh tcsh

Linux Password complexity rules:

1, use 4 kinds of characters wrongly written characters at least 3; 2, long enough, greater than 7, 3, using random strings, 4, periodic replacement, 5, the cycle is large enough;

Linux command format:Command option ParametersOptions:Short Options:-Multiple options can be combined:-a-b =-abLong options:--Parameters: The Action object of the command
Linux Professional nouns:

IDE: The integrated development environment (Integrated development environment) is an application for the provider development environment, typically including code editors, compilers, debuggers, and graphical user interface tools. DLL: dynamic link library English as DLL, is the short form of the dynamic link library, DLL is a library containing code and data that can be used by multiple programs simultaneously, DLL is not an executable file. . So: for a shared library, is a sharer object for dynamically connected directories:( working directory, current directory ) file, Path mapping path: The location from the specified starting point to the destination

Linux Command type:
built-in commands:(shell built-in), internal, built-in
external command:There is an executable file corresponding to the command name under a path in the file system
Linux Environment variables:

environment variable : named memory space variable assignment name=jerry Path: A colon-delimited path

From for notes (Wiz)

Linux Design Guidelines