I am trying to learn how to use umask but it seems so complicated.
Besides all the subtractions that I have to make in my head seperately for directories and files every time I see a mask value, the umask seems different at different times(see bellow).
For example if I have a mask of
it can also be seen as
umask -S u=rwx,g=rwx,o=rx
Why does the umask give
rwxrwxr-x and not
-------w- in this case? When I am given 0002 I am supposed to calculate the permissions for files by 666-002 and directories by 777-002. Shouldn't then
umask -S give me a similar thing so that I can calculate with. For example
negation-of(-------w-). So in one case it acts as a mask for negation and in the second case it just gives the result from what I understand. Why this ambiguous behaviour?