2016-7-3 Linux Learning Notes

file types for Linux

Dr-xr-xr-x. 4 root root 4096 June 09:57 boot

Ls

- L: Long Format

file type: the

-: Indicates normal file

D: catalog file

B: block device files (blocks)

C: character device file

L: Symbolic Link file (symbolic linkfile)

P: Command Pipe file (pipe)

S: socket file (socket)

file Permissions:9- bit, every three-bit group, each group:rwx ( read, write, execute )- Table no permissions

number of hard links to files

Owner of the file

genus Group of files

the size (size) of the file is inbytes (byte)

time stamp (timestamp) Last modified time

Access : Access

Modified : Modify

change : Change,metadata, meta data

-H: (Human Read) do unit conversions, change to human readable

-A : Display to . hidden files at the beginning

. represents the current directory

.. represents a previous level of directory

-A: does not display . and the .. the directory

- D : Displays the directory's own properties

- I. : Index Node,inode Displays the node number of the file

- R : Reverse Display

- R : Recursive Recursive display

Cd:change Directory Switch Directories

home directory, home directory, HomeDirectory

Cd ~username: Enter the home directory of the specified user

Cd-: switch back and forth between the current directory and the previous directory

Command type

built-in command (Shell built-in) internal, built-in like cd command

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External command: There is an executable file corresponding to the command name in a path on the file system

such as the SU command

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Type: Shows the type that the specified command belongs to

Environment variables: named memory space

assigning values to variables

Name=cary.qin

PATH: Environment variable , you can use printenv to print out the environment variables of the system

log the source path of the command executed by the system, using: Separate open

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Date : Time Management

Linux:RTC

NTP:network timeprotocol time server

hardware time:Hwclock

System Time

get help with the use of commands

Internal Command

Help Command

external Command

Command–help

Whatis command: See which chapter the commands help in

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Command manual:manual

Mans command

The Man command is divided into chapters:

1: User command

2: System call

3: library call

Man Flip Screen

Turn back one screen :space space bar

Turn One screen forward:b

Turn back one line: Enter Enter key

Turn One line forward:K

Hwclock

-W: system time synchronized to hardware SYSTOHC

-S: Hardware time synchronization to system Hctosys

online documentation

Info command

Cal:calendar Calendar

File commands and their usage

Rootfs: root file System

/ Boot : System boot-related files, such as kernel, INITRD, as well Grub

/dev: Device files, including "Block Device" and "character device"

/ etc : directory where the configuration file resides

home directory per user, default to /home/username(directory with the same name as the user)

/root: home directory for admin root

/lib: library file

static libraries,. A

dynamic libraries,. So

/lib/modules: kernel module Files

/media: mount point directory, Mount Mobile device

/mnt: Mount point directory, additional temporary file mount point

/OPT: Optional directory, installation directory for third-party programs

/proc: Pseudo file system, kernel mapping file, only after the system up there will be files

/sys: Pseudo file system, the property mapping file related to hardware device, only the file will be in the system.

/tmp: Temp file

/var: a variable file

/bin : Executable file, user command

/sbin : Manage Commands

/usr:shared,read-only

/usr/bin

/usr/sbin

/usr/lib

/usr/local: The path of third-party software storage

/usr/local/bin

/usr/local/sbin

/usr/local/lib

Naming rules:

1: Length cannot exceed 255 characters

2: Cannot use / when file name

3: Strictly case-sensitive

File Management

Directory Management

Ls

Cd

Pwd

Mkdir: Creating an empty directory

-P: recursive creation

-V:verbose show more information

Mkdir/mnt/test/{x/m,y} : command-line expansion creation, representing the creation of the /mnt/test/x/m and /mnt/test/y two directory files

Tree: Viewing the directory tree

This article is from the "Cary_qin blog" blog, make sure to keep this source http://xpqinqun.blog.51cto.com/2136/1795422

2016-7-3 Linux Learning notes