[-AI-3.5]Ten commands to Know to Control Linux System Processes

Abstract

この記事では、Linuxシステム上のプロセスを管理するために必要な十のコマンドについて説明しました。これらのコマンドを理解することで、自分自身でプロセスを制御することができます。プロセスを確認するには、psコマンドを使用し、実行中のプロセスの詳細を確認することができます。reniceコマンドを使用してプロセスの優先度を変更することもできます。killコマンドを使用してプロセスを強制終了することもできます。プロセスを監視するためには、topコマンドを使用することができます。さらに、execコマンドを使用することでプロセスを実行することもできます。これらのコマンドをマスターすることで、Linuxオペレーションを楽しむことができます。

Table of contents

• Introduction
• Displaying Processes: ps command
• Changing Process Priority: renice command
• Terminating Processes: kill command
• Monitoring Processes: top command
• Controlling Processes: nice command
• Examining Process Information: top, ps command
• Executing Processes: exec command
• Running Processes in Background: & operator
• Conclusion

-- CAUTION

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Introduction

Let’s learn about Linux process management. Sufficient knowledge is necessary to monitor processes on a Linux system. In this article, you will learn about the 10 commands necessary to control processes. By understanding these commands, you can control processes on your own. Let’s get started!

Display process: ps command

To control processes, it is important to first know how to display them. Linux has a command called ps that allows you to check the details of running processes.

The basic display method is simply entering the ps command. By default, it only displays processes of the user who is running it. However, to display all processes, use the -e option.

To display parent and child processes, use the -f option. To search and display using the parent process ID, use the -p option.

Finally, to display processes in a tree structure, use the -H option. This is a useful way to understand the relationships between processes and how they are managed.

Using the ps command to display processes can be helpful for monitoring processes or stalking specific processes. However, accessing unknown processes requires caution.

Change the priority of a process: renice command

Among the 10 commands you should know to control the processes of a Linux system, let’s introduce the renice command to change the priority. The renice command is used to change the priority of a running process.

To check the priority, you can use the ps command to examine the process priority. To change the priority, execute the renice command by specifying the priority. To limit the scope of process selection, you can specify the group ID with the -g option or the user ID with the -u option. Furthermore, if you want to specify the range, you can execute the command by specifying the process ID with the -p option.

Also, if you only want to change the priority of the specified process, you can execute the command by specifying the process ID with the -p option. If you want to specify multiple processes, you can separate them with a comma.

However, you must be careful because it may affect the performance of the entire system. If inexperienced users change the priority unintentionally, the system responsiveness may decrease. Therefore, you should use it carefully.

End the process: kill command

One way to end a process is to use the kill command. With the kill command, you can forcibly terminate a specified process or send a signal to terminate it. If you want to forcibly terminate a process, use the -9 option. You can also terminate a process with a specified signal. Before using the kill command, it is important to check the type of signal.

Note: When using the kill command, be careful as it may affect other processes.

Monitor processes: top command

To monitor processes, Linux has a top command. With this command, you can monitor the operation of processes in real-time, and also pause and resume them. You can also re-arrange processes by priority using this command and search for processes using keywords. By mastering the use of this command, you can always be aware of the status of processes.

However, there may be cases where the information provided by the top command is too abundant. In such cases, using the command ’htop’ provides a more concise display of information. Htop provides a more user-friendly interface than the top command and may support split terminal displays.

When monitoring processes, the top command may not necessarily be the most optimal option. Commands like Iostat and Sar can be used to monitor the system’s overall load. These commands can also be useful for tuning the overall performance of a system.

Control the process: nice command

The nice command is used to control the priority assigned to processes. It allows you to assign and maintain priority for running processes even after they have been restarted. This command is very useful for managing system resources such as CPU and memory.

By raising or lowering the priority of processes, you can also improve performance. If you have processes that require a certain level of priority, you can assign it regardless of personal preference.

However, be careful. Raising the priority too much can monopolise essential resources for other processes and potentially lower overall system performance. Adjusting process priorities should be done carefully, with attention to the overall system performance.

Examine process information: top, ps command

To investigate process information, top and ps commands are useful. The ps command can display process information in a list format. Additionally, the top command can check the CPU usage and memory usage of processes. It can also display the information of running processes graphically and display information of the process specified by pid. With these commands, you can easily investigate process information. However, to avoid confusion from excessive information, extract only the necessary information. Master the commands and strive for efficient work.

Execute the process: exec command

The way to execute a process is to use the exec command. This command can start a new process, set environment variables to run a process, or set file descriptors to run a process. To start a new process, specify the name and arguments of the program you want to run as arguments to the exec command. To set environment variables, use the export command, and to set file descriptors, use the redirection operator.

Run the process in the background: & operator

In Linux, you may want to continue using the terminal window while running a command. In such cases, the & operator is convenient as it allows you to run the command in the background. Additionally, you can use the jobs command to display background jobs and the fg command to switch a job running in the background to the foreground for operation. With proper use of these commands, you can work more efficiently.

Conclusion

I introduced 10 commands related to process control that are useful for beginners using Linux. There are commands necessary for process control such as ps, renice, kill, top, nice, exec, &, etc. By mastering these, you can enjoy operating Linux.