Umask command details, umask details

Umask command details, umask details

The linux system assigns default permissions to the created files and directories.

The default parameter umask is 0022.

View the created file and directory permissions.

The File Permission is rw-r --

The directory permission is rwxr-xr-x.

0022 the first 0 can be ignored. The 022 permission is ---- w -- w-

The default permission of the file is 666, that is, rw-; the permission of the directory is 777 rwxrwxrwx.

Therefore, umask is used to perform subtraction Calculation for default permissions to obtain initial file and directory permissions.

Default file creation permission (rw-)-(---- w -- w-) = (rw-r --)

Default directory permission (rwxrwxrwx)-(---- w -- w-) = (rwxr-xr-x)

Do not subtract the umask value from a number. It is wrong.

The command umask 002 used to change the value of umask directly follows the permission value to be subtracted.

After the change, I will calculate the permission again.

Create a file (rw-)-(------- w-) = (rw-r --)

Create directory permission (rwxrwxrwx)-(------- w-) = (rwxrwxr-x)