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Recursive chown gone wrong: How to avoid changing ownership of unintended directories

Ubuntu 18

In the realm of Linux system administration, the chown command is a powerful tool that allows you to change the ownership of files and directories. However, when used improperly, it can lead to unintended consequences. This article will delve into the issue of recursive chown operations going wrong, and how to avoid changing the ownership of unintended directories.

Quick Answer

To avoid changing ownership of unintended directories when using the chown command, it is important to avoid using the * wildcard and instead specify the actual directory you want to change ownership for. By being cautious and double-checking your commands, you can prevent unintended consequences and maintain the desired ownership of your files and directories.

Understanding the chown Command

The chown command is used in Linux to change the user and/or group ownership of a given file or directory. The basic syntax of the chown command is as follows:

chown [OPTION]... [OWNER][:[GROUP]] FILE...
  • OWNER specifies the new owner of the file/directory.
  • GROUP is optional and specifies the new group.
  • FILE is the file or directory whose ownership you want to change.
  • OPTION is used to modify the behavior of the command. The -R or --recursive option is commonly used to change the ownership of a directory and its contents recursively.

The Issue with Recursive chown

The problem arises when the chown command is run with the -R (recursive) option and the * wildcard. The * wildcard matches all files and directories in the current directory. This includes the parent directory (..), causing the ownership to be changed for both the current directory and its parent directory.

For instance, if you run sudo chown -R admin:admin * from within the /home/admin directory, it will change the ownership of all files and directories within /home/admin, including the parent directory /home.

How to Avoid Unintended Ownership Changes

To avoid changing the ownership of unintended directories, it is recommended to specify the actual directory you want to change ownership for, rather than using the * wildcard.

Solution 1: Specify the Directory

To recursively change ownership for the /home/admin directory, you can use the following command:

sudo chown -R admin:admin /home/admin

In this command, -R makes the command recursive, admin:admin sets the new owner and group, and /home/admin is the directory whose ownership will be changed.

Solution 2: Exclude the Directory Itself

If you want to recursively change ownership for the files inside the /home/admin directory, excluding the directory itself, use the following command:

sudo chown -R admin:admin /home/admin/*

Here, /home/admin/* specifies all files inside /home/admin, but does not include the directory itself.

Conclusion

The chown command is a powerful tool, but it must be used with caution. When used improperly, it can lead to unintended changes in ownership. By specifying the actual directory you want to change ownership for, rather than using the * wildcard, you can avoid changing the ownership of unintended directories. Always double-check your commands before running them, especially when logged in as the root user or using sudo.

For more information on the chown command, you can check the official Linux documentation.

What is the purpose of the `chown` command?

The chown command is used to change the user and/or group ownership of a file or directory in Linux.

How do I use the `chown` command?

The basic syntax of the chown command is chown [OPTION]... [OWNER][:[GROUP]] FILE.... You specify the new owner and/or group, and the file or directory you want to change ownership for.

What does the `-R` option do in the `chown` command?

The -R or --recursive option in the chown command is used to change the ownership of a directory and its contents recursively.

What happens when I use the `*` wildcard with the `-R` option in the `chown` command?

When you use the * wildcard with the -R option, it matches all files and directories in the current directory, including the parent directory (..), which can lead to unintended changes in ownership.

How can I avoid changing the ownership of unintended directories?

To avoid changing the ownership of unintended directories, it is recommended to specify the actual directory you want to change ownership for, rather than using the * wildcard.

How do I recursively change ownership for a specific directory?

To recursively change ownership for a specific directory, you can use the command sudo chown -R [OWNER]:[GROUP] /path/to/directory, where [OWNER] is the new owner and [GROUP] is the new group.

How do I recursively change ownership for files inside a directory, excluding the directory itself?

To recursively change ownership for files inside a directory, excluding the directory itself, you can use the command sudo chown -R [OWNER]:[GROUP] /path/to/directory/*.

What should I be cautious about when using the `chown` command?

When using the chown command, be cautious about the ownership changes you are making, especially when using the -R option. Always double-check your commands before running them, especially when logged in as the root user or using sudo.

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