Umask Calculator

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).