Daily development of common commands in Linux

Record common commands in daily development of Linux

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start java program

(1) Start directly, and close the application when the console exits
java -jar xxxxxx.jar

(2) Background startup, console exit will not turn off the application
nohup java -jar xxxxxx.jar &

(3) Start the background and output the log, the console exit will not turn off the application
nohup java -jar xxxxxx.jar >> ./projectStart.log 2>&1 &

(4) Start in the background (add memory) and output logs, console exit will not turn off the application
nohup java -jar -Xms1024m -Xmx2048m xxxxxx.jar>> ./projectStart.log 2>&1 &2>&1 &

turn off an app

(1) Query the java application process (grep is followed by conditional filtering)
ps -ef | grep java

(2) Forcibly kill the process
kill -9 process number

View port netstat

netstat -nltp //Note: View all ports
netstat -ano | grep :8081 //Note: View the programs running on port 8081
netstat -ano | grep :8081 |wc -l //Note: View the total number of connections on port 8081

Firewall command: firewall

Close the firewall or open the port so that other hosts can access it

systemctl start firewalld //Comment: Open the firewall
systemctl stop firewalld //Comment: Close the firewall
systemctl status firewalld //Comment: View the firewall status
firewall-cmd --zone=public --list-ports //Comment: View all ports opened by the firewall Port
firewall-cmd --permanent --zone=public --add-port=8081/tcp //Note: Add a firewall to open ports to the outside world (add a single port)
firewall-cmd --reload //Note: Reload the firewall configuration
firewall -cmd --zone=public --list-ports //Note: View all ports opened by the firewall

nginx related: start stop restart

1. The executable directory sbin starts nginx
   /usr/local/nginx/sbin/nginx
   or first enters the executable directory sbin
   cd /usr/local/nginx/sbin/
   and then executes
   ./nginx // Note: start
   ./nginx -s stop //Note: Stop method 1
   ./nginx -s quit //Note: Stop method 2
   ./nginx -s reload //Note: Restart

2. nginx.service starts nginx
   cd /usr/lib/systemd/system/
   This directory must have nginx.service, if not, it must be configured, otherwise the following commands cannot be executed:
   systemctl start nginx.service // Note: start nginx
   systemctl stop nginx.service //Note: Stop nginx
   systemctl restart nginx.service //Note: Restart nginx
   systemctl status nginx.service //Note: View the current nginx status Execution results are divided into two types>> Active: failed [This means it is closed] Active: active (running) [this indicates the running state]

3. The configuration file is specified to start nginx
   /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
   Note: nginx installation directory path -c nginx configuration file path parameter -c specifies the configuration file path, if not specified, the default configuration file is used

Full disk search by filename

find / -name xxxxxx.txt // Note: / can be followed by a path to limit which directory, -name is followed by the target file name to be searched

Common errors (continuously updated)

• -bash: ./startup.sh: Permission denied
  Reason: This is because there is no execution permission. Just add execute permissions.
  Solution: Add execution permission to the target file
  chmod +x xxxxxx.sh or chmod 777 xxxxxx.sh

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