Basic Linux Knowledge

Basic knowledge of Linux and related concepts

One, the distribution version of Linux

The so-called release version is the Linux kernel + open source program

• Debain,ubuntu Ubantu is a derivative version of Debain, desktop system is better, suitable for beginners.

• Slackware, SusE

• Redhat,centos,fedora Centos,fedora is a derivative version of Redhat, and Fedora is primarily a new technology for testing redhat. CentOS is primarily a community version of Redhat and is free to use.

• ArchLinux

• Gentoo is used for technical cattle and the installation process is complex.

• LFS is a shorthand for Linux from scratch, and building a simple Linux distribution from scratch is a good choice for understanding Linux compilation parameters.

Second, the philosophical thought of Linux

• All documents

• Consists of a number of small programs with a single function; Each applet accomplishes a single thing
  

• Assemble small programs to accomplish complex tasks

• Avoid human interaction as much as possible, and facilitate script writing

• Use a text file to save configuration information

• Through mechanisms, not policies

Iii. Common Open Source agreements

• GPLv2, GPLv3

  • GPL protocol is more stringent, as long as the use of the GPL code, must be open source
    

• Lgpl:lesser

  • Loose GPL protocol, application of library files for knowledge, can not open source
    

• Bsd:

  • If the source code is included in the two released product, it must be in the source code with the BSD protocol in the original code

  • If you publish a library or program in binary format two times, you need to include the BSD protocol in the original code in the published document or copyright notice

  • The author/organization of the Open source code and the original product name can not be marketed

• Apache License:

  • The Apache protocol is the same as the BSD protocol specification
    

Iv. Features of Bash

• Command and path completion

  • Find commands that start with a user-specified string based on how the built-in command or external command looks

  • File name completion lookup with user-specified start path
    

  • If the user-specified start string uniquely identifies a command or path, the TAB key can complete the command or path. Otherwise, the TAB key is two times to display all commands that begin with the specified string or all files under the specified path

• Command line expansion

  • ~: Expand to User home directory

  • ~username: Expand the home directory for the specified user

  • {} Expand with polynomial multiplication, for example/tmp/{a,b}/{c,d} to/tmp/a/c,/tmp/a/d,/tmp/b/c,/tmp/b/d.

V. File hierarchy of Linux (FHS)

• /bin,/sbin: The system itself starts and runs when the user's core binary commands may be

• /lib: Shared library files and kernel modules

• Shared library files and kernel modules for the/lib64:64-bit system

• /etc: Configuration file

• /usr:

  • /usr/bin,/usr/sbin: A command that a user may use to complete certain operations during a system run

  • /usr/lib,/usr/lib64: library file

  • /usr/share/man,/usr/share/doc: Application manuals or help documents

• /dev:devices, the device files for all devices are stored here; Device files are often also referred to as special files (metadata only, no data)

• /proc: Pseudo file system, kernel and process information of the virtual file system interface, like the system system, CPU, memory are abstracted into the file placed in this directory

• /sys: Pseudo file system, hardware device information virtual file system interface

• /boot: Static files used during system boot loading, kernel and RAMDisk (CENTOS5:INITRD,CENTOS6:INITRAMFS), Grub (bootloader)

• /home/username: Specify the user's home directory

• /root:root User's home directory

• /MNT: Path of temporary file mount

• /media: Mount path of portable device, like u disk, CD

• /SRV: Data used by the service

• /tmp: Temporary file storage location

• /var: Files that change frequently

  • /var/log: Log files for each application are stored inside

• /misc: Alternate Directory

• /OPT: Installation directory for third-party applications

  • /usr/local: Now the Software installation directory

• /selinux Security Enhanced Linux: Secure and enhanced Linux

Vi. unit conversions in Linux

• 8 bit = 1 Byte

• 1024x768 B = 1 K

• 1024x768 K = 1 M

• 1024x768 M = 1 G

• 1024x768 G = 1 T

• 1024x768 T = 1 P

• 1024x768 P = 1 E

• 1024x768 E = 1 Z

• 1024x768 Z = 1 Y

Vii. Definition of free software

• Free to use

• Free Learning and modification

• Free distribution

• Free to create derivative versions

To be Continued ...

This article is from the "After Dark" blog, be sure to keep this source http://guoting.blog.51cto.com/8886857/1433602