Getting Started with Linux systems basics

1, describe the composition of the computer and its functions

The computer has five major components: an operator, a controller, a memory, an input device, and an output device.

The arithmetic is responsible for data processing and data operation, and is generally integrated in the CPU

The controller is responsible for the control of the computer equipment; Generally integrated in the CPU

Memory is responsible for recording the storage data used, such as hard disk, memory, etc.

The input device is responsible for the computer accepting instructions from other devices, such as keyboard, mouse, etc.

The output device is the device responsible for outputting computer processing results, such as monitors, etc.

2. List Linux distributions by series and describe the connection and difference between different distributions.

Linux has three major distributions

Slackware was developed and released two times, and SuSE is more popular. SLEs is an enterprise-class use, and openSUSE is a desktop-class

Debian is a distributed version of the open source community, which has developed and released Ubuntu Systems two times;

Redhat is divided into Rhel and Fedora,rhel are enterprise-oriented systems, very stable and reliable, fedora is a user-oriented system for personal use, updated very fast, the latest features, CentOS system is fully compatible with Rhel, and eventually by Redhat company acquisition, Become a product.

3, describe the philosophy of Linux, and according to their own understanding of its interpretation of the description.

The philosophy of Linux is first and foremost a document that organizes almost all resources, including hardware, into file formats;

The second is composed of a number of single-purpose small programs; A program that implements only one function and does it well, combining small programs to complete complex tasks

As far as possible to avoid interacting with the user, the purpose is to implement script programming, to automate certain functions;

Using plain text files to save configuration information, the purpose is to use a text editor can not only complete the system configuration work;

4, description of the use of the command on the Linux system format, details Ifconfig, Echo, TTY, STARTX, export, pwd, history, shutdown, Poweroff, reboot, Hwclock, the use of the date command , and is elaborated in conjunction with the corresponding example.

Linux commands are generally used in the following formats: #command [Options ...] [Arguments] command-option parameter

The function of the ifconfig command is used to view network-related situations;

Ifconfig does not add any options and parameters to see how the current local network adapter works

- A displays all information, including the network card in the inactive state

Up enable specifies the NIC name before specifying the NIC up

Down to specify the NIC name before the specified NIC is down

Echo Output content to screen command

echo $SHELL: Displays the current user's SHELL type by default \ n line break

TTY shows current terminal without parameters

StartX start X Window graphical interface without parameters

Export lists or modifies the values of environment variables

-F represents the function name in [variable name].

-n Deletes the specified variable. The variables are not actually deleted, but are not exported to the execution environment of the subsequent directives.

-p lists all the environment variables that the shell assigns to the program.

Example: Export myenv=7//Define environment variables and assign values

PWD Displays the current working directory

-L directory connection link, output connection path

-P Output Physical path

Historical History Command File

No parameter is a history command that displays the current user;

-A is append the current command to the history command file;

-d command to delete the commands specified in history

-C is the total purge history command;

Environment variables: Histcontrol ignoredups ignore repeating consecutive values default

Ignorespace commands that begin with ignoring spaces

Ignoreboth: Ignore last two

Call History Command:

!#: Execute the # command

!! Executes the previous command

!string: Executing an instruction at the beginning of a character

Shutdown shutdown Command

-R reboot

-C Cancel

-H too long time off

now says

+ Time: Indicates how long after the beginning of the shutdown, the unit minutes hh:mm absolute time, 24-hour format;

Example: Shutdown +5 #过5分钟后关机

Shutdown-c #取消关机

Poweroff no parameters, direct shutdown-F Force shutdown

Reboot reboot the system without parameters to restart immediately.

-D do not write data to the record file when restarting/var/tmp/wtmp

-F Force reboot, do not invoke the function of shutdown instruction.

-H put all the hard drives in standby mode before the system shuts down or Poweroff

-I shut down network settings and then restart the system

-N Save the data and then restart the system

-p tests only, does not really turn the system on again, only writes the data of the reboot to/var/log

Wtmp record file under directory

Hwclock: Display hardware time

-S with hardware time quasi-synchronous

-W in system time quasi-synchronous

Date: Displays the current system time

Date [OPTION] ... [+format]

Format: Formatting symbols

%T: Time

%F Month Day

%d Date only

%w Week

%m Month

%y Two-bit year%y four-bit

Date [-u|--utc|--universal] [MMDDHHMM[[CC]YY][.SS]: Set time

MM Month

DD Date

HH hours

MM min

YY Two-bit year

CCYY four-bit year

. SS seconds

Example: ~]# date-u 080414182016 #设置系统时间为2016年8月4日14点18分

5, how to get the Help information of the command on the Linux system, please detailed list, and describe how the chapters of the man document are divided.

External command help information in Linux, you can use the Man command to view

Mans COMMAND

The following sections are generally included in the Help manual

NAME

Synopsis

DESCRIPTION

OPTIONS

EXAMPLES

AUTHOR

REPORTING BUGS

See ALSO

Synopsis;

The different symbols represent different meanings:

[]: Optional content

<>: Required Content

A|b: Two Choose one

...: The same content can appear multiple times

How to operate the man command:

Space,^v,^f page

B,^b PAGE Up

D,^b Turn Half page

U,^u up half a page

Erturn: Next line

Y,^y Previous Line

Q: Exit

#: Jump To Line #

1G First Line

G: Last line

Man file different chapters also have different meanings

Man1 (User command), man2 (System call), MAN3 (library call)

MAN4 (device files and special files) man5 (configuration file format)

Man6 (game). Man7 (Miscellaneous). MAN8 (Management Class)

Internal commands are usually followed by commands to view the Help file with--help

6, please list the Linux distribution version of the basic directory name of the law and function provisions

The Linux distribution directory typically contains the following names:/etc,/usr,/var,/root,/home,/dev

With file system root filesystem

/boot: Boot file directory; kernel file vmlinux, boot loader grub

/bin: Basic command for all users, unable to associate separate partitions, programs that are used by OS startup

/sbin: Management class Basic Command; Cannot associate a separate partition, the program that is used by OS startup

/lib: Basic shared files, and kernel module files; (/lib/modules)

/LIB64: Dedicated to the storage location of the secondary shared library files on the x86_64 system;

/etc: Configuration file

/home/username: General user home directory;

/root; Administrator home Directory;

/media: Portable mobile device hangs at point

/MNT: Temporary file system hangs at the point;

/dev device files and special files

/OPT: Third-party application installation location;

/SRV: Data used by services running on the system;

/tmp; temp file

/usr; Universal Shared,read-only Data

Bin  Sbin Ensure that the system has the complete application provided by the function

LIB,LIB64 Library file

Include c The header file of the program;

Share structured independent data

Local: The installation location of the third-party application.

Bin,sbin,lib,lib64,etc,share ...

/var:variable Date File

Cache: Application Caching directory

LIB: Application state information data

Local: Application-variable data dedicated to/usr/local/

Lock, locking file

LOG: Logs directory file

OPT: variable data for applications dedicated to/usr/opt/

Run: Running process-related data, storing the process of the PID file;

Spool: Application Data Pool

TMP: Temporary data that is dedicated to system restart

/proc: Used to output the virtual file system of the kernel related to process information.

/sys: A virtual file system for outputting information about hardware devices on the current system.

/selinux:security enhanced Linux. SELinux-related security policy information

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Getting Started with Linux systems basics