How to Recursively Change the File's Permissions on Linux

Shweta Singh -

Introduction

You may encounter a situation where you try to create or edit a file and receive a "Permission denied" error if you use Linux as your primary operating system or manage Linux servers. In most cases, issues caused by insufficient rights can be resolved by changing file permissions or ownership.

Because Linux is a multi-user operating system, file permissions, characteristics, and ownership are used to control access to files. Only authorized users and processes can access files and folders as a result of this.

See "Umask Command on Linux" for additional information about file permissions.

In this tutorial, we'll show you how to alter the permissions of files and directories in a recursive manner. We will also address a few FAQs on how to recursively change the file's permissions on Linux.

Chmod Recursive

You can use the chmod command to modify the permissions of files in either symbolic or numeric mode.

Use the chmod command with the -R(--recursive), option to recursively work on all files and directories under a particular directory. To recursively change the file's permissions, use the following syntax:

chmod -R MODE DIRECTORY

To set the permissions of all files and subdirectories in the /var/www/html directory to 755, for example, type:

chmod -R 755 /var/www/html

The symbolic method can also be used to specify the mode:

chmod -R u=rwx,go=rx /var/www/html

A file's permissions can only be changed by root, the file owner, or a user with sudo access. When recursively modifying the permissions of files, be extra cautious.

Using the find Command

In general, the permissions of files and directories should not be the same. The execute permission is not required for most files, but you must establish execute rights on directories in order to change into them.

The most usual scenario is to set the permissions of the website file to 644 and the directory's permissions to 755.

Using the numerical approach:

find /var/www/html -type d -exec chmod 755 {} \;
find /var/www/html -type f -exec chmod 644 {} \;

Use the symbolic method:

find /var/www/html -type d -exec chmod 755 {} \;
find /var/www/html -type f -exec chmod 644 {} \;

The find command looks for files or folders in /var/www/html and feeds them to the chmod command, which sets permissions on them.

When running find with -exec, the chmod command is executed for each identified entry. Use the xargs command to pass multiple items at once to speed up the process.

find /var/www/html -type d -print0 | xargs -0 chmod 755 
find /var/www/html -type f -print0 | xargs -0 chmod 644

FAQs to Recursively Change the File's Permissions on Linux

How do I grant read, write, and execute permissions to the file owner, group, and other users?

You can use the notation chmod -R u=rwx,g=rwx,o=rwx [directory/file] to assign read, write, and execute permissions to the owner, group, and others recursively.

Can I recursively change permissions for directories only, without affecting files?

Yes, you can use the find command in combination with chmod to specify which type of file (e.g., directories) you want to change permissions for. For example, find [directory] -type d -exec chmod [permissions] {} \; will change permissions for directories only.

How can I remove execute permissions from all files within a directory recursively?

You can use the command chmod -R a-x [directory] to remove execute permissions recursively from all files within the specified directory.

What do the different numeric values in file permissions represent?

The numeric values 4, 2, and 1 represent read, write, and execute permissions, respectively. By adding these values, you can assign combined permissions (e.g., 7 for read, write, and execute).

Is it possible to change ownership recursively along with permissions?

Yes, you can use the chown command with the -R option to recursively change ownership for files and directories.

What precautions should I take before recursively changing file permissions on Linux?

It is important to carefully review the permissions you are assigning and understand their implications. Changing permissions recursively can have unintended consequences, so ensure you choose the appropriate permissions and target directories/files correctly. Always backup critical data before making any changes.

Can I use wildcard characters to select multiple files or directories for changing permissions recursively?

Yes, you can use wildcard characters like * or ?. For example, chmod -R 755 /path/to/directory/* will change the permissions recursively for all files and directories within the specified directory.

Conclusion

You can modify the permissions of a file recursively using the chmod command with the -R arguments.

Use chmod with the find command to recursively set permissions on files based on their type.

If you have any queries, please leave a comment below and we’ll be happy to respond to them.