Linux Common Commands 1

Ls

List is used to display target lists

Grammar

ls [Options ...] [Arguments ...]

Options

-A all displays all files and directories (including hidden files that begin with.) and the directory itself. and the parent directory. ）

-A shows all hidden files excluded with. and. All the files

-L Long displays detailed information in long format (

The output information is from left to right, including file name, files type, permission mode, hard connection number, owner, group, file size

Small, last modified time and filename of the file

-F Appends the type identifier of the file to the output item (no identifier is output when the file is a normal file)

* Indicates an ordinary file with executable permissions

/indicates directory

@ denotes symbolic link

| Represents a command pipeline FIFO

= indicates sockets socket

-C and-lt line selection installation file status time sort output sort by the CTime field in the index node of the file when it is in conjunction with the –l line, the order is based on the state change time of the file

-D Show only the directory itself

-I display file index node number (inode)

-k display file size in kilobytes

-R sorts and outputs a list of directory contents in reverse order of file names

-S displays the file and directory size, in chunks

-T sorts the file and directory change times

-R Recursive processing

--color uses different colors to highlight different types of

Cd

Change Directory switch working directory to dirname dirname notation can be an absolute path or a relative path

Omit dirname switch Current user home directory

~ Indicates the user's home directory

. Represents the current directory

.. Represents the top-level directory of the current directory

Grammar

CD [Options ...] [Arguments]

Options

-P If the destination directory to switch directories is a symbolic link, switch directly to the target directory to which the symbolic link is directed

-L if the target directory of the switch is a symbolic link, switch directly to the directory represented by the word linked, the destination directory to which the non-symbolic link is directed

-When only this option is used, the switch to the previous switch directory is indicated.

type

Displays the type of the specified command (internal command or external command)

Command type:

Alias aliases

Keyword keyword, shell reserved word

function functions, Shell functions

Builtin built-in command, Shell built-in command

file files, disk files, external commands

Unfound not found

Grammar

Type [Options ...] [Arguments]

Options

-T output file, alias, or Builtin indicates that directives are external, command aliases, and internal commands, respectively

-P If the given instruction is an external instruction, its absolute path is displayed

-A displays information for a given instruction in the path specified by the environment variable "path"

File

The hash table is the object that the shell first looks for when interpreting the command, and the shell uses the set path to find the command when the instruction does not exist in the hash table. It will also be placed in a hash table. The next execution is no longer re-searching through path (can provide shell command execution efficiency)

Hash

Grammar

hash [Options ...] [Arguments]

Options

-R clear Hash table record

-P add command to hash table

Date Time management

Hardware clock: Clock

System clock: Date

Hwclock

-w:--SYTOHC

-s:--hctosys

Get help with the use of commands

Internal command:

Help COMMAND

External command:

COMMAND--help

Command manual: Manual

Man [NO.] COMMAND

Sub-chapters:

1: User command (/bin,/usr/bin,/usr/local/bin)

2: System call

3: library Call

4: Special files (device files)

5: File Format (configuration file syntax)

6: Game

7: Miscellaneous

8: System administration Command (/sbin,/usr/sbin,/usr/local/sbin)

Online documentation

Info COMMAND

System Help Documentation

/usr/share/doc

Whatis

Whatis COMMAND

cal Calendar

Echo

Printf

Tree

Directory Management Commands

mkdir Creating an empty directory

-P

-V

rmdir only empty directories can be deleted

-P

File Management Commands

Touch

-C

-A

-M

Stat

Rm

-I.

-F

-R

CP Copy

Mv

Linux Common Commands 1