perl function umask

The umask function in Perl is used to set the current umask value. The umask value is a set of bits that determine the default permissions for newly created files and directories.

Here's the syntax for the umask function:

umask $mask_value

where $mask_value is an integer value representing the new umask value.

And here's an example that shows how to use the umask function:

umask 022;
open(my $filehandle, '>', 'new_file.txt');
close($filehandle);

In this example, we set the umask value to 022, which means that newly created files will have default permissions of 644 (readable and writable by the owner, and readable by everyone else). We then create a new file named new_file.txt using the open function, and close the file using the close function. Since we didn't explicitly set any permissions for the file, it will inherit the default permissions based on the umask value we set.

Note that the umask function affects the current process and all child processes that are forked from it, until the umask value is changed again.