CHMOD Calculator

Setting file permissions on Unix-based systems can be tricky. The CHMOD Calculator simplifies the process by providing an easy-to-use interface for calculating and generating the necessary commands. Just check the boxes for the desired permissions, and the calculator will display the corresponding CHMOD values and commands. It’s a handy tool for anyone working with files and directories on Unix-based systems.


Owner Group Other
Read (r)
Write (w)
Execute (x)







In Unix-based systems, every file and directory has a set of permissions that control the level of access granted to different users. These permissions determine who can read, write, or execute the file. Here’s a brief overview of the three categories of users:

  • Owner: The user who created the file or directory. The owner has the ability to set permissions and typically has full control over the file.
  • Group: A collection of users who share certain access rights to the file. Each file is associated with one group.
  • Others: Any user who is not the owner of the file and not part of the group. This category represents everyone else.

Permissions are represented by three characters for each category, and they follow this order: owner, group, others. Each character can be a combination of:

  • Read (r): Permission to view the contents of the file or list the contents of the directory.
  • Write (w): Permission to modify the file or add/remove files from the directory.
  • Execute (x): Permission to run the file as a program or enter the directory and perform operations within it.

Permissions Best Practices and Guidelines

Understanding file permissions and applying them correctly is crucial for maintaining a secure and well-organized system. This section provides detailed explanations, best practices, and guidance on setting appropriate file permissions for different scenarios using our calculator.

File Permissions Explained

File permissions in Unix-based systems like Linux determine who can read, write, or execute a file or directory. There are three user categories: Owner, Group, and Others. Each category can be granted or denied Read (r), Write (w), and Execute (x) permissions using the calculator

Web Server Permissions

When running a web server, it’s essential to configure file permissions correctly using the chmod calculator to prevent unauthorized access and potential security breaches. Here are some recommended practices:

Document Root Permissions

  • Set the web server’s document root directory to 755 (rwxr-xr-x) using the chmod calculator to allow the web server to read and execute files while restricting write access.

Configuration File Permissions

  • For sensitive configuration files or scripts, use 644 (rw-r–r–) or 600 (rw——-) with the chmod calculator to restrict access to the owner only.
  • Regularly review and update file permissions using the chmod calculator, especially after installing new applications or making changes to the server.

Database Permissions

Proper file permissions set using the chmod calculator are crucial for databases to ensure data integrity and prevent unauthorized access. Consider the following guidelines:

Database File Permissions

  • Set permissions for database files (e.g., data files, log files) to 600 (rw——-) or 640 (rw-r—–) using the chmod calculator to restrict access to the database owner or group.

Configuration File Permissions

  • For database configuration files, use 644 (rw-r–r–) or more restrictive permissions with the chmod calculator if necessary.
  • Grant the database user or group read and write access to the database files and directories using the appropriate chmod settings.

User File Permissions

When dealing with user-generated files or content, it’s essential to implement proper permissions using the chmod calculator to protect user privacy and prevent unauthorized access. Follow these best practices:

User-Uploaded File Permissions

  • Set user-uploaded files and directories to 644 (rw-r–r–) or 640 (rw-r—–) using the chmod calculator to allow the owner and group to read and write while restricting access for others.
  • Consider using stricter permissions like 600 (rw——-) with the chmod calculator for sensitive user data or files containing personal information.
  • Implement appropriate file ownership and group assignments based on your application’s requirements.

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