In Linux systems, understanding the relationship between files and processes is a very important task. The fuser command allows you to see which processes are using a specific file, directory, or filesystem. Today, let’s learn about this super useful command—fuser.1. What is the fuser Command?The fuser command is used to display which processes are using the specified file, directory, or filesystem. It can help you understand the relationship between files and processes and resolve issues with files being in use.Before diving deeper into thefusercommand, it is recommended to check its official documentation to understand all available options and usages. Enter the following command in the terminal:
man fuser2. Usage of the fuser CommandBasic command format:
fuser [options] file|directory|filesystemCommon options: -k: Kill processes using the file. -m: Display processes using the specified filesystem. -u: Show the user to whom the process belongs. -i: Confirm before killing the process. -n: Specify the namespace to use. -c: Show process count. -s: Do not display the header. -w: Show task numbers.3. Example OperationsExample 1: View processes using a specific file
fuser /home/shishun/a.txt# This command will display the processes using the /home/shishun/a.txt file.Example 2: View processes using a specific directory
fuser /home/shishun# This command will display the processes using the /home/shishun directory.Example 3: View processes using a specific filesystem
fuser -m /home/shishun/a.txt# This command will display the processes using the /home/shishun/a.txt filesystem.Example 4: Kill processes using a file
fuser -k /home/shishun/a.txt# This command will kill the processes using the /home/shishun/a.txt file.Example 5: Display the user to whom the process belongs
fuser -u /home/shishun/a.txt# This command will display the processes using the /home/shishun/a.txt file and their corresponding users.Example 6: Display process count
fuser -c /home/shishun/a.txt# This command will display the count of processes using the /home/shishun/a.txt file.4. Practical TipsScenario 1: Resolving file in use issuesWhen you cannot delete or move a file that is in use, you can use the following command to find the processes occupying that file and kill them:
fuser -k /home/shishun/a.txtScenario 2: Monitoring filesystem usageYou can use the following command to monitor the usage of a specific filesystem:
watch -n 1 'fuser -m /path/to/filesystem'# This command will refresh every second, displaying the processes using the /path/to/filesystem filesystem.Scenario 3: Analyzing processes with other commandsYou can combine it with the ps command to get more information about the processes:
ps aux |grep $(fuser /home/shishun/a.txt)# This command will display detailed information about the processes using the /home/shishun/a.txt file.5. PrecautionsPermission requirements:Some options (like -k) may require administrative privileges to execute, so you may need to prepend sudo when using them.Safe operations:Killing processes is a high-risk operation that may lead to data loss or system instability. When using the -k option, ensure you know what you are doing.Output explanation:The output of the fuser command includes process IDs and may also include user information (if the -u option is used).6. Interactive SessionQuestion 1:How do you use the fuser command to view processes using a specific file?Question 2:How do you kill processes using a file when using the fuser command?If you already know the answers, or if you have other questions while using the fuser command, feel free to leave a comment for discussion! Let’s communicate and improve together.