Linux operation commands

1, the operation of the file directory

(1) ls: Display directories and files

Syntax: ls [选项] [目录或文件]: Display the files in the next level of the path;

Common options：

(1) -a: List all files in the directory, including .hidden files starting with ;

(2) -k: The size of the file is expressed in k bytes;

(3) -l: List the details of the file

(4) -r: Sort the directory in reverse

(5) -t: Sort by time

(6) -R: List files in all subdirectories
(7) ls /: Display all files in the root directory

Notice：ls /bin =ls ./bin = ls bin

The first one is the absolute path writing method, the last two are the relative path writing method

Linux, .the file at the beginning represents a hidden file;

(2) cd: switch to a directory

• cd 路径: switch to a directory

cd ~: switch to user directory

cd /: switch to the root directory
cd -: return to the most recently accessed directory
cd ..: return to the parent directory

(3) pwd: Display the directory where the current user is located

pwd: Displays the directory the user is currently in

Notice：

(1) Several special directories:

• /root directory
• .called the current directory
• ..the parent directory called the current directory

(2) Absolute path and relative path:

• /Absolute paths starting with
• start with .or ..start with as a relative path

(3) tabKey completion;

When entering, if you forget to include those files, enter twice and you tabwill be prompted~

(4) touch: change document/directory date

touch 文件路径: If the file exists, modify the last update time of the file to the current time, if it does not exist, create a new file ( 不是文件夹);

(5) mkdir : create a directory

mkdir 目录名称: Create a directory

Here is to create a tdirectory named, if it already exists, an terror will be reported;

If the path has multiple levels, use -p;

(6) rm: delete file/directory

rmPath to file or directory: Delete a file or directory

By default it will prompt

Create a new one text.txt, use -fDelete, there will be no prompt message

-r: Recursively delete all contents in the directory

Notice: rm -rf /must not do this arbitrarily

(7) cp: copy files/directories

grammar:cp 源文件或目录 目标文件或目录

eg : Copy the test.txtfile to the tdirectory:

-R: copy folder

(8) mv: move the file to the target directory

mv 源路径 目标路径: move a file to a directory

eg : test.txtmove to tthe folder

move the tdirectory test.txtto the current directory and name ittest2.txt

2, the operation of the file content

(1) cat: View the contents of the target file

cat 文件路径: show all the contents of the file

(2) vi: text editor

Two modes:

• read-only mode:Can not be modified

Read-only mode to enter edit mode :
(1) Press i: the current cursor position, insert new content;
(2) Press o: the next line of the current cursor, insert a new line;
exit the program: input ：wqsave and exit ( wmeans save, qmeans exit) Enter ：q!Force exit without saving;
search :
/搜索的内容: The cursor moves to the first matching position, and when pressing n, switches to the next matching position, and shift+nswitches to the previous one;
g连点两下: The cursor switches to the beginning of the document;
shift+g: The cursor switches to the end of the document;
restore Last modified content: press u;

• edit mode: The keyboard input will be inserted into the text

Edit mode to enter read-only mode: pressesc

(3) less: view file content

grammar:less [参数] 文件

parameter:

• -NDisplay the line number of each line

show:

Click qto exit; j: scroll up the screen; k: scroll down the screen;

(4) head: Display the content of the file

head -n 行数 文件路径: Display the content of the file, and display the total number of lines from the front to the back
eg: Display the content of the test.txtprevious 10line
as follows:

(5) tail: display file content

tail -n 行数 文件路径: Display the content of the file, from the last line to the previous [line number]
as shown below :

Pipe |: The way of inter-process communication: the output of the left process is used as the input of the right process;

eg：输出test.txt第10行的内容

common usage：

To output a file, the contents of lines from x to y:

• head -n[y] 文件路径 | tail -n[y-x+1]
• tail -n[总行数-x+1] 文件路径 | head -n[y-x+1]

Such as :显示 test.txt 文件中，从 第 6 行到第10行的内容

(6) grep: find whether the file contains the specified string

grep “搜索的内容” 文件/目录路径: Search in a file or directory and match the searched content

Often with the pipe symbol, the output of a certain instruction is searched for:

Such astest.txt : 10search for a string in the previous element, freturn if there is, not return if not;

3. man view instruction command

man 命令名称: Viewing the description of a command ( 包括命令参数)
will enter the document reading mode;

in:

j：向下一行翻 k：向上一行翻 q：退出

/ 搜索的内容: Search for the matching string, after the search is found, press nto find the next matching position, and press to shift+nmatch the previous one; (This is also done in document reading mode)
g: switch to the first line of the document, shift+g: switch to the end of the document;

eg: searchall

4. About the network

(1) netstat: View the network status on the system

netstat -anp: Display network information for all processes

If not, you need to install a package first, the command is:
yum install -y net-tools

Among them :

• yum: means to download and install a program online through the network;
• install: indicates installation;
• net-tools: package name;

(2) ps: View the processes running on the current system

ps: View process information

(1) ps aux | grep "进程名称/pid"
(2)ps -ef | grep "进程名称/pid"

Generally speaking, first find the process netstatby the port number pid, and then use psby to pidfind the process information;