Contents
- System Service Management
- file management
- view log
- Compression and decompression
- Disk and Network Management
- firewall
- ftp operation
- Installation and Management of Software
- Other
System Service Management
systemctl
The state of each service in the output system:
systemctl list-units --type=service
View the running status of the service:
systemctl status firewalld
Shut down service:
systemctl stop firewalld
Start up service:
systemctl start firewalld
Restart the service (whether the current service is started or closed):
systemctl restart firewalld
Reload configuration information without interrupting service:
systemctl reload firewalld
No service boot-up self-startup:
systemctl disable firewalld
Set up service boot-up self-start:
systemctl enable firewalld
file management
Finding Documents
(Find the filename.txt file in / directory by name)
find / -name filename.txt
View files, including hidden files
ls -al
List all files under the current directory (/):
ls
ls -l /
Get the absolute path to the current working directory
pwd
Change the current working directory: cd
cd /usr/local
Display or modify system time and date;
date '+%Y-%m-%d %H:%M:%S'
Used to set user passwords: passwd
passwd root
Change User Identity (Switch to Super User):su
su -username
Used to clear screen information
clear
Display help information for the specified command:man
man ls
What level of operation is the query system at?
who -r
Displays users currently logged in to the system:
who -buT
Display system memory status (unit MB): free
free -m
Display system process running dynamics: ps
ps -ef
View the running dynamics of the sshd process:
ps -ef | grep sshd
View Real-time Active Processes, Similar to Windows Task Manager
top
Create directories
mkdir
Copy files including their subfiles to a custom directory
cp -r sourceFolder targetFolder
Delete directories (this directory is empty)
rmdir deleteEmptyFolder
Delete files including their subfiles
rm -rf deleteFile
Delete files: rm
rm text.txt
move file
mv /temp/movefile /targetFolder
Move or overwrite files: mv
mv oldNameFile.md newNameFile.md
Modify file permissions (file.java permissions - rwxrwxrwx, r for read, w for write, x for executable)
chmod 777 file.java
Used to view the contents of a file for too long pages:
View boot.log file at 10 lines per page
more -c -10 /var/log/boot.log
View the Linux startup log file file and mark the line number: cat
cat -Ab /var/log/boot.log
Create the text.txt file:touch
touch text.txt
Start Vi Editor
vi filename
1) Enter editing mode
shift+i
2) Withdrawal from editing mode
esc-->shift+:
3) Deposit and Exit
wq
4) Forced withdrawal
q
view log
Look at the file header for 10 lines
head -n 10 example.txt
Look at the bottom 10 lines of the file
tail -n 10 example.txt
View the log file (this command automatically displays the new content, and the screen only displays 10 lines of content (settable)
tail -f exmaple.log
Search for keywords in the log
less server.log
1) If you want to start searching from the first line of the log
Less server. log - > / search keyword - > n to find the next - > N to find the last one
2) If you want to start searching from the last line of the log
Less server. log - > shitf + G - >? Search keywords - > n to find the last - > N to find the next
Compression and decompression
decompression
unzip FileName.zip
//Compression:
zip -r FileName.zip DirName
File files in the / etc folder into file etc.tar (without compression): tar
tar -cvf /mydata/etc.tar /etc
Compress files in folder / etc to file etc.tar.gz with gzip:
tar -zcvf /mydata/etc.tar.gz /etc
Compress folder / etc to file / etc.tar.bz2 with bzip2:
tar -jcvf /mydata/etc.tar.bz2 /etc
Page to view the contents of the compressed package (gzip):
tar -ztvf /mydata/etc.tar.gz |more -c -10
Unzip the file to the current directory (gzip):
tar -zxvf /mydata/etc.tar.gz
Disk and Network Management
View disk usage
df -h
View disk usage
free
View disk space occupancy:
df -hT
dh
View the size of files and folders in the current directory:
du -h --max-depth=1 ./*
Display the current network interface status
ifconfig
View the current routing information: netstat
netstat -rn
View all valid TCP connections:
netstat -an
View the monitoring services started in the system:
netstat -tulnp
View a port listening service in the system:
netstat -ntlp|grep 8080
View system resource information in connection state:
netstat -atunp
Check to see if a process exists
ps -ef|grep java/pid
Download files from the network
wget
firewall
There are two kinds of firewall software in Linux, firewall is used above ConterOS 7.0, and iptables are used below ConterOS 7.0. This article will introduce the use of two kinds of firewall software.
Firewall
Open the firewall:
systemctl start firewalld
Close the firewall:
systemctl stop firewalld
View firewall status:
systemctl status firewalld
Set boot start:
systemctl enable firewalld
Disable boot-up:
systemctl disable firewalld
Restart the firewall:
firewall-cmd --reload
Open Port (Firewall Restart is required to take effect after modification):
firewall-cmd --zone=public --add-port=8080/tcp --permanent
View open ports:
firewall-cmd --list-ports
Close the port:
firewall-cmd --zone=public --remove-port=8080/tcp --permanent
Iptables
install
Since the version of CenterOS 7.0 or above does not pre-install Iptables, we need to install them ourselves.
Close firewall firewall before installation
Install iptables:
yum install iptables
Install iptables-services:
yum install iptables-services
Open the firewall:
systemctl start iptables.service
Close the firewall:
systemctl stop iptables.service
View firewall status:
systemctl status iptables.service
Set boot start:
systemctl enable iptables.service
Disable boot-up:
systemctl disable iptables.service
Look at several chain rules of the filter table (the INPUT chain shows which ports are open):
iptables -L -n
Look at the chain rules of the NAT table:
iptables -t nat -L -n
Clear all rules of firewall:
iptables -F
iptables -X
iptables -Z
Add rules to the INPUT chain (open port 8080):
iptables -I INPUT -p tcp --dport 8080 -j ACCEPT
Find the line number of the rule:
iptables -L INPUT --line-numbers -n
Delete the filter rule according to the line number (close port 8080):
iptables -D INPUT 1
ftp operation
ftp ip
Enter password;
bin converts files to binary
get gets the file name
Installation and Management of Software
rpm
Installation package:
rpm -ivh nginx-1.12.2-2.el7.x86_64.rpm
Fuzzy Search Software Package:
rpm -qa | grep nginx
Find the package accurately:
rpm -qa nginx
Query the installation path of the package:
rpm -ql nginx-1.12.2-2.el7.x86_64
View the package summary information:
rpm -qi nginx-1.12.2-2.el7.x86_64
Verify that the package content is consistent with the installation file:
rpm -V nginx-1.12.2-2.el7.x86_64
Update the package:
rpm -Uvh nginx-1.12.2-2.el7.x86_64
Delete packages:
rpm -e nginx-1.12.2-2.el7.x86_64
yum
Installation package:
yum install nginx
Check for updatable packages:
yum check-update
Update the specified package:
yum update nginx
Find package information in the repository:
yum info nginx*
List all packages installed:
yum info installed
List the package names:
yum list nginx*
Fuzzy Search Software Package:
yum search nginx
Other
Termination threads (threads that terminate thread number 19979)
kill -9 19979
Check the number of threads (to see if the program is wrong)
Ps-Lf port number | wc-l
View Network Connectivity
ping ip
Check the connectivity of the ip port (firewall connectivity)
telnet ip port - > exit mode shift +] - > quit
View local ip
ifconfig
View Scheduler
crontab -l
Edit Scheduler
crontab -e
To learn more about Facebook and develop small skills, you are welcome to scan the two-dimensional code below, and continue to pay attention to it!
