As a senior website operations expert, I am well aware of the importance of a stable and reliable content management system for a corporate website.AnQiCMS (AnQi Content Management System) boasts its efficiency and concise architecture in Go language, providing an excellent content management experience for numerous enterprises.However, even the most powerful system also needs correct deployment and maintenance to ensure its continuous and efficient operation.start.shThe one that seems insignificant in the script.nohupWhat crucial role does this command play, ensuring that AnQiCMS can continuously and uninterrupted serve your website?

AnQiCMS The cornerstone of continuous operation:start.shThe guardian of scripts

When discussing the deployment of AnQiCMS on Linux servers, especially in command-line environments without a visual interface (such as Baota Panel Go project management)start.shThe script is the core for starting and maintaining the AnQiCMS service.This script is not only responsible for starting the binary program of AnQiCMS, but more importantly, it is designed as a 'guardian' to ensure that AnQiCMS can run stably even under various external disturbances.

Ininstall.mdandstart.mdIn the document, we can all seestart.shThe key content of the script. The most core startup command is like this: 

cd $BINPATH && nohup $BINPATH/$BINNAME >> $BINPATH/running.log 2>&1 &

This command may seem complex, but it is the magic that keeps AnQiCMS running continuously. To better understandnohupThe function of the command, we first need to understand a common Linux process "death" reason.

Understanding the risk of "terminal hang"

In Linux systems, when we connect to a server via SSH and run a program directly in the terminal (such as./anqicmsThis program becomes the "child process" of the current terminal session. This means its lifecycle is closely tied to your terminal session.

Once you close the terminal window, or the SSH connection is disconnected due to network issues, the system will send a signal namedSIGHUPThe signal (suspended). Most programs will default to terminating execution upon receiving this signal.

Imagine if your AnQiCMS were to start up like this, then if you accidentally close the terminal, or the server administrator goes home for the day, the website would be inaccessible the next day due to service interruption.This is an unacceptable high risk for any website that requires 24/7 online availability.

nohup: ResistingSIGHUPthe solid shield

nohup命令，全称是 “no hang up”，字面意思就是“不挂断”。它的核心作用就是让其后的命令忽略SIGHUP.

When the startup command of AnQiCMS is prefixed withnohupthe system will know: Even if the terminal session ends, the AnQiCMS process should continue to run, do not stop becauseSIGHUPSignal and terminate. This is like putting a sturdy protective suit on AnQiCMS, making it no longer subject to the limitations of the terminal session lifecycle.

at the end of the command.&Symbols, it is a supplementary function, indicating that the command is executed in the background.Thus, after starting AnQiCMS, the terminal will immediately return to the command line prompt, allowing you to continue executing other operations without waiting for the AnQiCMS program to finish.

nohupWith&The combination ensures that AnQiCMS can continue to run stably in the background even after the user logs out, becoming a true 'daemon process'.

Output redirection: neat and traceable log management

In the above command, besidesnohupand&we also saw>> $BINPATH/running.log 2>&1This part is about redirecting program output, which is also crucial for stable operation in production environments.

  • >> $BINPATH/running.logThis means appending all standard output (stdout) of the program torunning.logthe file.
  • 2>&1This indicates that the standard error output (stderr, file descriptor 2) is redirected to the same place as the standard output (file descriptor 1), that is,running.logfile.

Why should this be done?

  1. Avoid terminal blocking and file creationIf notnohup, the program output will be printed directly to the terminal. But even if there isnohupIf the output is not redirected, it may still try to write to/dev/nullor the files in the current directorynohup.outThis may lead to unnecessary disk I/O or file fragmentation.
  2. Log recording and fault diagnosis: Concentrate all the running logs of AnQiCMS (including normal output and error information) intorunning.logIn the file, valuable data is provided for daily system monitoring and fault troubleshooting.When AnQiCMS encounters problems, operation personnel can conveniently view the logs, understand the program's running status, and quickly locate and solve the problem.

Combinecrontab: Build a robust self-healing system

The document also mentions addingstart.shthe script tocrontab(Scheduled Tasks), and set it to run once a minute. This is equivalent tonohupCommand together has built a highly robust AnQiCMS running environment:

  • start.shThe script will first check if AnQiCMS is running.
  • If AnQiCMS stops for some reason (such as program crash, memory overflow, etc.),existsthe variable will be 0.
  • At this time,start.shit will execute again.nohup ... &命令，AnQiCMS would be automatically restarted.

This "heartbeat detection" and "auto-restart" mechanism has raised the stability of AnQiCMS to a new level.Even under unattended conditions, AnQiCMS can recover from unexpected failures in a short period of time, ensuring the continuous online operation of the website to the maximum extent. This is a reflection of AnQiCMS's focus on 'high concurrency, security, and scalability' in its design, and it is what our operations team is most pleased to see.

Summary

nohupCommand in AnQiCMS'sstart.shscripts is by no means unnecessary. It is related to the background running symbol&, output redirection, andcrontab

Common Questions (FAQ)

  1. 问：If I do not usenohupcommand to directly start AnQiCMS, what will happen?答：If you do not usenohup命令，AnQiCMS的进程将直接绑定到您当前的终端会话。一旦您关闭终端窗口、SSH连接断开或网络出现故障，系统会向该进程发送SIGHUPSignal, leading to the termination of AnQiCMS service, your website will not be accessible.

  2. Question: AnQiCMS service has been enablednohupHow do I stop it after it starts and runs in the background?Answer: BecausenohupThe process started by the command has detached from the terminal, you cannot stop it directly by closing the terminal. You need to find the PID (Process ID) of the AnQiCMS process, then usekillTerminate the command. Usually, you can useps -ef | grep anqicmscommand to find the process ID of AnQiCMS, then usekill -9 [PID](Among which[PID]is the process ID found to force stop. Of course, AnQiCMS'sstop.shscripts usually encapsulate these operations and run directly./stop.shwill be more convenient and safe.

  3. Q:running.logWhat is the function of the file? Will it keep growing?Answer:running.logThe file records all standard output and error information of the AnQiCMS program, which is an important basis for diagnosing the program's running status and troubleshooting.Information generated by the program at runtime will be appended to this file.running.logThe file may become very large. To avoid the log file being too large and occupying too much disk space, it is recommended to use Linux log rotation tools (such aslogrotateRegularly archive, compress, and delete old log files.