Unix Permissions & Chmod Generator | Free Online Permissions Tool

Generate, calculate, and understand Unix file permissions with this free online tool, and llows you to generate Unix permissions in numerical and symbolic formats.


Generated Permission Command

Octal Chmod Command

chmod 0700 file_name

Symbolic Chmod Command

chmod u=rwx,go= file_name
Enter Permission

Example: symbolic format: o+wx or stat format: --x--x--x or number format: 644

Permission Visual Editor
User rights (u)
Group rights (g)
Others rights (o)
Read (4)
Write (2)
Execute (1)
Settings
setuid
setgid
sticky bit
recursive
preserve-root
reference file

Quick Permission Examples

How to Use the Unix Permission Generator

1

Set Permission

Enter permission text or toggle the checkboxes under User, Group, and Others to set read (r), write (w), and execute (x) permissions with permission-visual-editor.

2

Configure Special Modes (Optional)

Enable SUID, SGID, or Sticky Bit options if you need special access control for your files or directories.

3

Generate Permission

Permission will be automatically generated based on the configuration.

4

Apply Permission

Paste the generated unix permission command into your terminal to apply the permission to your files or directories.

Frequently Asked Questions

Unix file permissions are a security mechanism that controls who can access, modify, or execute a file or directory. There are three main permission types: read (r), write (w), and execute (x), which can be applied to three different user categories: the file owner, the group owner, and others.

Octal notation uses numbers (0-7) to represent permissions, where each digit corresponds to the permissions for the owner, group, and others. For example, 644 means the owner can read and write, while the group and others can only read.

Symbolic notation uses letters (r, w, x) and operators (+, -, =) to modify permissions. For example, u+rwx,g+rx,o-rwx adds read, write, and execute permissions for the owner, adds read and execute for the group, and removes all permissions for others.

SUID (Set User ID): When set on an executable file, the file runs with the permissions of the file's owner rather than the user executing it. This is commonly used for commands like passwd that need elevated privileges.

SGID (Set Group ID): When set on an executable file, the file runs with the permissions of the file's group. When set on a directory, new files created within that directory inherit the directory's group rather than the user's primary group.

Sticky Bit: When set on a directory, it prevents users from deleting or renaming files in that directory unless they own the file or the directory. This is commonly used on the /tmp directory.

You can use the chmod command followed by either the octal or symbolic notation to change file permissions. For example:

chmod 644 filename.txt  # Octal notation
chmod u+x filename.sh   # Symbolic notation

The first command sets the file to be read-write for the owner and read-only for the group and others. The second command adds execute permission for the owner of a shell script.

Directories typically need the execute permission to allow users to enter them. Common directory permissions include:

  • 755 (rwxr-xr-x) - Read, write, and execute for the owner, and read and execute for the group and others. This is common for public directories.
  • 775 (rwxrwxr-x) - Read, write, and execute for the owner and group, and read and execute for others. This is common for shared directories.
  • 700 (rwx------) - Read, write, and execute only for the owner. This is common for private directories.