Linux Basic Command Summary

1. Modify the command prompt

Environment variable: PS1:

\u: Current user name

\h: Host Name

\h:fqdn, host name in full format

\w: The base name of the current working directory

\w: The current working directory absolute path

\$: Prompt

\ t: Show time

View command: Echo $PS 1

Modify command: ps1= ' [\u\h \w]\$ '

2. Change the directory:

Cd:change Directory

CD ~ Switch to the current user's home directory

CD ~username switch to the home directory of the specified user

CD-: Repeatedly switch between the previous directory and the current directory

Two unique paths:

.: Current Directory

.. : Top level Directory

3. Command history:

History N: Displays the nearest n, including the current command itself;

History-c: Emptying command history

history-d Offset: Delete the command entry at the specified offset

History-a [/path/to/some_history_file]: Writes the history of a command in the current session to the specified file

Bash invokes commands in the command history list:

!#: Execute the # command in the history of the command

!: Executes the previous command

!string: Executes the last command in the command history that begins with string;

!$: Call the last parameter of the previous command

ESC,.: function Ibid.

Environment variables that change the way the history is recorded:

Histcontrol:

Ignoredups: Ignoring duplicate commands, successive identical commands will be duplicated

Ignorespace: Ignore commands that begin with whitespace characters

Ignoreboth: The above two counterparts enter into force;

4. Shutdown command:

Shutdown-h shut down the machine

-R Restart

-C Cancel shutdown operation

Time format

Now

+m

hh:mm

Reboot: Restart

Halt: Shut down the machine

Poweroff: Shut down the machine

5. Time setting:

Date: Day and Time

date [options] [+format]

%s: Timestamp timing, number of seconds from the beginning of Unix (1970-01-01 00:00:00) to this moment

%F,%d

%T

%Y

%m

%d

%H

%M

%s

Set Time:

Date [MMDDHHMM[[CC]YY][.SS]]

Linux has two clocks: system clock and hardware clock

Hardware clock:

System clock: Linux

Hwclock (Administrator privileges to view)

-S: Subject to Hardware

-W: System-based

6. Directory Management

Mkdir:make Directory

-P: When the parent directory of the specified target directory does not exist, it is created first

-V: Show more information

Rmdir:remove Directory

-P: Delete Directories in the only son directory path

One of the bash features: command line expansion

~: User Home Directory

~username: Specify the user's home directory

{}:

/tmp/{x,y}

/tmp/x,/tmp/y

/tmp/{x,y}/z

/tmp/x/z,/tmp/y/z

7. View commands

ls command: List shorthand

ls [option] [file]

Common options:

-l:long, long format displays detailed property information for a file

Drwxr-xr-x. 2 root root 4096 Feb 09:55 account

First from left: file type

The following 9-bit: permissions, often called mode

R: Reading, read

W: Writing, write

X: Execute, Excute

.: Indicates file has hidden properties

lsattr command to view

Number: Number of times this file has been hard-linked

Master: Owner, owner of File

Group: Group, groups to which the file belongs

4096: File size, Unit is byte

-h:human-readable, automatic unit conversion

The time the file was last modified

Filename

-A: Show All Files

-D: Typically used with-l to display only the directory's own properties

-r:reverse, Reverse display

-r:recursive, recursive display, displaying content in subdirectories

Stat: Displays metadata for a file

Timestamp information:

Access (Atime): Indicates the last time the file was accessed

Modify (Mtime): Indicates when the file content was last modified

Change (CTime): Indicates when the file metadata was last modified

If the mtime changes, CTime must follow the change.

CTime change, mtime not necessarily change.

Touch: Changing the file's Atime and Mtime,ctime is maintained by the file system itself.

Touch [option] ... FILE

If file does not exist, an empty file is created by default

-A: Change atime only

-M: Change Mtime only

-C: Do not create empty files

-T [[CC]YY]MMDDHHMM[.SS]

Cat: Connect and display text file contents

A text file is a stream of data: Stream streaming

-E: Display line terminator

for Linux, the line break is $, and for Windows the line break is two characters: newline character $+ carriage return, so the Linux text file is opened in Windows with TXT in a row without line breaks, But Linux can recognize Windows line breaks.

-N: Show line numbers

TAC: Displaying file contents in reverse order

7.5 echo Command

echo [-nee] [arg ...]

\ n

\ t

\v Vertical Tab

\033[

Single digit: Control font

3#: #是一个数字, 3 indicates control of its foreground color

4#: #是一个数字, 4 indicates control of its background color

To use in combination with one another; separate.

eg

The background is blue and the foreground is green:

Echo-e ' \033[32;44mhello\033[0m '

Bold:

Echo-e ' \033[32;1mhello\033[0m '

M: is a fixed format

\033[0m: The function of the controller ends here

7.6 Other display commands: More,less,head,tail,

8. Aliases: Alias

Alias Alias=command

When aliases have the same name as the command:

Absolute path

\command

Effective Scope: The alias of the command line definition, which takes effect from the current session; ******

Unalias [ALIAS]

-A: Undo all aliases

9. File Management class command:

Copy: CP

Mobile: MV

Delete: RM

Cp:

CP SRC DEST

SRC is a file:

If Dest does not exist: copy src to dest

If dest exists:

If Dest is a file: overwrite

If Dest is a directory: copy src into the dest and keep the original

CP SRC ... DEST

If there is more than one SRC, the dest must be a directory;

CP SRC DEST

SRC is the directory:

You can use the-r option:

Cp-r SRC ... DEST

-P: Copy the symbolic link file itself instead of the destination file it points to

--preserve[=attr_list]

Mode,ownership,timestamps

Mode: Permissions

owership: Belong to the master, genus Group

timestamps: Time stamp

-P: equivalent to--preserve=mode,ownership,timestamps

-A: equivalent to-DR--preserve=all

Archive: Archive

-i:interactive

-f:force

MV Command:

MV SRC ... DEST

-i:interactive

RM command:

-I: Interaction

-F: Force delete

Delete root:

--no-preserve-root

10. Text Processing Class command:

Wc:word Count

-L: Show only the number of rows

-W:

C:

Cut

-D: Specify delimiter

-F: Specify the fields to display

M: Column M

M,n: section m and N columns

M-n: section m to nth column

Sort

Sort [option] FILE ...

-F: Ignore character case

-T: Specify delimiter

-K: Specifies the field to be compared after separation

-N: Sorting by numeric size

-U: Go back after sorting

Uniq: deduplication (only two consecutive rows are considered duplicates)

-D: Show only duplicate rows

-U: Show only rows that have never been duplicated

-C: Count the number of rows that appear

11. Other:

Ntp:network time Protocol (no longer used after REDHAT7)

Synchronizing system time over a network

Ntpdate SERVER

Who: All users logged on to the current system

WHOAMI: User logged on at the current terminal

Which: Displays the full path of the specified command

--skip-alias: Passing Command aliases

Type of file content:

File/path/to/somefile

Command Call Cache:

Hash

-D: Clears cached content for the specified name

-R: Empty cache

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Linux Basic Command Summary