Umask Calculator
Results:
Numeric Umask: 000
Effective Permissions: rwxrwxrwx
The umask command in Linux is used to set the default permission modes for newly created files and directories. When a new file or directory is created, the system uses the umask value to determine the initial permissions
How umask Works
The umask value is a three-digit octal number that determines which permission bits to turn off when a new file or directory is created. To understand how umask affects the permissions, let’s look at the default permission settings for files and directories:
- Default file permissions:
666
(read and write for everyone, no execute) - Default directory permissions:
777
(read, write, and execute for everyone)
When a new file or directory is created, the umask value is subtracted from these defaults to determine the final permissions. For example, if the umask is set to 022, the permissions for new files and directories would be:
- Files: 666 – 022 = 644 (read and write for owner, read-only for group and others)
- Directories: 777 – 022 = 755 (read, write, and execute for owner, read and execute for group and others)
Examples of umask
To make it easier to understand how different umask values affect file and directory permissions, here’s a table with several examples.
umask Value | File Permissions | Directory Permissions | Description |
---|---|---|---|
000 | 666 | 777 | Full permissions for everyone (read, write) for files and (read, write, execute) for directories. |
022 | 644 | 755 | Owner can read and write files, others can only read. Directories are executable by everyone. |
027 | 640 | 750 | Owner can read and write files, group can read, others have no access. Directories are executable by owner and group. |
077 | 600 | 700 | Only owner has read and write permissions for files, and full control for directories. |
002 | 664 | 775 | Owner and group can read and write files, others can only read. Directories are executable by everyone. |
0177 | 600 | 700 | Same as 077 (only owner has full control). |
Setting and Viewing umask
To view the current umask value, simply type umask in the terminal:
umask
To set a new umask value, use the umask command followed by the desired value:
umask 027
This command sets the umask to 027, which means new files will have permissions 640 and new directories will have permissions 750.