I'll get straight to the point.
When I started Pop!_Planet, I launched it because I saw a need for a centralized community for Pop!_OS. To be frank, I never expected the level of popularity it has achieved. Over the last year, we have gone from under 50 users, to almost 400 users. That's awesome! However... it also comes with a downside. We are rapidly running out of disk space on our server, and the bandwidth costs go up every month.
Pop!_Planet is not affiliated with System76 in any way, and is funded completely out of pocket. From day one, I said that I'd never use on-site ads (I hate them as much as you do), so the only monetization we get is through donations. Right now, the donations we receive don't even cover our overhead.
I know that most users will ignore this message, and that's ok. However, if even a few of our users are willing and able to donate a few dollars to help offset our expenses, it would be greatly appreciated.
Thank you for your time,
The umask utility is used to control the file-creation mode mask, which determines the initial value of file permission bits for newly created files. The behavior of this utility is standardized by POSIX and described in the POSIX Programmer's Manual. Because umask affects the current shell execution environment, it is usually implemented as built-in command of a shell.
The mode mask contains the permission bits that should not be set on a newly created file, hence it is the logical complement of the permission bits set on a newly created file. If some bit in the mask is set to
1, the corresponding permission for the newly created file will be disabled. Hence the mask acts as a filter to strip away permission bits and helps with setting default access to files.
The resulting value for permission bits to be set on a newly created file is calculated using bitwise material nonimplication (also known as abjunction), which can be expressed in logical notation:
R: (D & (~M))
777for directories, but only
For example, let us assume that the file-creation mode mask is 027. Here the bitwise representation of each digit represents:
0stands for the user permission bits not set on a newly created file
2stands for the group permission bits not set on a newly created file
7stands for the other permission bits not set on a newly created file
With the information provided by the table below this means that for a newly created file, for example owned by
User1 user and
User1 has all the possible permissions (octal value
7) for the newly created file, other users of the
Group1 group do not have write permissions (octal value
5), and any other user does not have any permissions (octal value
0) to the newly created file. So with the
027 mask taken for this example, files will be created with
||write and execute|
||read and execute|
||read and write|
||read, write and execute|
To display the current mask, simply invoke
umask without specifying any arguments. The default output style depends on implementation, but it is usually octal:
-S option, standardized by POSIX, is used, the mask will be displayed using symbolic notation. However, the symbolic notation value will always be the logical complement of the octal value, i.e. the permission bits to be set on the newly created file:
$ umask -S
chmod 700, as applied by
useradd -m) sufficient, as they make all files within unaccessible to other users. Should this not be practical (for example when using Apache), and public files are stored amongst private ones, then consider restricting the umask instead.
You can set the umask value through the umask command. The string specifying the mode mask follows the same syntactic rules as the mode argument of chmod (see the POSIX Programmer's Manual for details).
System-wide umask value can be set in
/etc/profile or in the default shell configuration files, e.g.
/etc/bash.bashrc. Most Linux distributions set a default value of
022. You can also set umask with
pam_umask.so but it may be overridden by
/etc/profile or similar.
If you need to set a different value, you can either directly edit such file, thus affecting all users, or call
umask from your shell's user configuration file, e.g.
~/.bashrc to only change your umask, however these changes will only take effect after the next login. To change your umask during your current session only, simply run
umask and type your desired value. For example, running
umask 077 will give you read and write permissions for new files, and read, write and execute permissions for new folders.