Linux Learning Notes [Continuous Update]

Keywords: Linux CentOS vim

Linux Notes
Installation section:
swap virtual memory is twice as large as memory, such as 4G (no setting if large)
Boot partition master boot 500M
/Root Full Allocation
You can also create a / data that can be used to mount things

Configuration section:

hostnamectl set-hostname name  #Set Host Name
exec bash    #Refresh

Remote ssh login

ssh root@

File viewing section:

Ls-R | wc-l where -R is a recursive view and WC is a statistic of how many rows there are
Ls-l View file properties rw-r--r and so on are owner, group, other permissions
File can see the file format
cd - Back to the last directory
vim!$A little confused (last character of last command)
Exclamation mark to call last command
If the previous one executed rm-rf*
Then!Rm=rm-rf *

Create a directory:

mkdir -p 1/2/3  #Recursive creation
mkdir test{1,2,3}perhaps mkdir test{1..99}Create 99
touch 123     #create a file
echo 123123   #Display 123123
echo 123123 >1.txt  #Write 123123 in 1.txt

File lookup:

which: find command
locate: database-based lookup, fast lookup, need to update the database
find: traversal search, slow search, accurate (commonly used)

User and file rights management:


vim /etc/passwd   #User Profile
vim /etc/group    #Group Profile
vim /etc/shadow   #User Password File
vim /etc/gshadow  #Group Password File
vim /etc/sudoers  #User Title File

User Add

useradd -u 3000 openstack  #Create a user name OpenStack with uid 3000

User Rights

chown: Modify the file or directory to belong to the master/group

chown student ahdifu/  #Modify the ahdifu folder to belong to student

Modify file permissions

uRepresents the owner of the file
gGroup representing file
oOther Users
aUsers Used
+Add permissions
-Delete permissions
=Give privileges directly
chomd u+w file  #Subordinate to Groups to Increase w Permissions
chomd o=wrx file  #Give wrx (write, read, execute) permissions to other users
chomd u-w file  #Delete w permissions belonging to groups
chomd 0765 file  #Abbreviation

Supplement: ll-d filename=ls-ld filename

File Access Control List

setfacl: file access control list, set permissions for specific users
-m Set Permissions
-x Revoke permissions

setfacl -m u: student: rwx ahdifu/  #u means for the user

getfacl can see detailed groups and permissions

sticky permissions


SGID Permissions (Required)

chmod u+s filename
chmod g+s filename
chmod o+t filename

text processing

grep tool:

Used to filter information

grep sh /etc/shells

Filter effect as shown in the diagram

chattr +i test
lsattr test.txt  #Even root users cannot delete modifications after use

Network management:

ip addr #View local ip address information
systemctl status network.service #Old Version
systemctl status NetworkManager #8.3 Network Management Tools
nmcli connection up ens160   #Use this refresh if the ip does not change after configuring the network
ifconfig ens160 down
ifconfig ens160 up

Network reboot is required to edit network card profile directly

nmcli conn up ens160 = nmcli connection up ens160
nmtui   #Commands can be used to configure network cards

The above commands are based on the NetworkManager tool, and if the service is not turned on, the configuration of the network ip address cannot be modified.

systemctl status NetworkManager
systemctl stop NetworkManager
systemctl start NetworkManager
systemctl enable NetworkManager  #Start-Up Self-Starting
systemctl disable NetworkManager  
nmcli connection show #View all network card connections
nmcli connection reload
nmcli connection up eth0
 The above two are equivalent to those in version 7/etc/init.d/network restart

The following commands view port usage

netstat -tunalp
netstat -tunlp | grep 8080 #View specified port usage
##netstat can be replaced with ss

Software management:

Installation of software:

rpm -ivh package_name #Multiple software packages can be installed at the same time, either locally or on the network

For example, we installed tree-1.7.0-15.e18.86_64rpm
Find/mnt-name tree This command finds a file named tree
This command checks to see if it is installed by default: rpm-qa tree*
(If so, delete the file using rpm-e package_name)
Next enter the installation command rpm-ivh t*, (t=tree)
Select tree-1.7.0-15.e18.86_64rpm to install

Decompression tool:

tar compression tool

-cCreate archive file
-xExtract Archive File
-cSpecify the extraction location, defaulting to the current directory
-fSpecify the archive file to operate on
-tList which files are in the archive
-vShow archiving process
-excludeExclude a file

Common compression tools on Linux:
-z uses gzip compression
-j uses bzip2 compression
-J uses xz compression
General combination usage:

tar -czvf #Create an archive and gzip compression
tar -xzvf #Extracting gzip compressed archive files
tar -cjvf #Create an archive and use bzip2 compression
tar -xjvf
tar -cJvf #Create archives and use xz compression

Other compression tools (zip compression tools)
Use which zip to see if zip is installed or if not

zip /root/ * #Compress all files in the current directory to / root / and name them
uzip /root/ /root/jieya  #Unzip to jieya folder

Posted by joukar on Mon, 13 Sep 2021 14:50:13 -0700