5.1.  Umask Settings

  The umask command can be used to determine the default file creation
  mode on your system. It is the octal complement of the desired file
  mode. If files are created without any regard to their permissions
  settings, the user could inadvertently give read or write permission
  to someone that should not have this permission. Typically umask
  settings include 022, 027, and 077 (which is the most restrictive).
  Normally the umask is set in /etc/profile, so it applies to all users
  on the system.  The file creation mask can be calculated by
  subtracting the desired value from 777.  In other words, a umask of
  777 would cause newly-created files to contain no read, write or
  execute permission for anyone.  A mask of 666 would cause newly-
  created files to have a mask of 111.  For example, you may have a line
  that looks like this:



                       # Set the user's default umask
                       umask 033




  Be sure to make root's umask 077, which will disable read, write, and
  execute permission for other users, unless explicitly changed using
  chmod.  In this case, newly-created directories would have 744 permis­
  sions, obtained by subtracting 033 from 777.  Newly-created files
  using the 033 umask would have permissions of 644.

  If you are using Red Hat, and adhere to their user and group ID
  creation scheme (User Private Groups), it is only necessary to use 002
  for a umask.  This is due to the fact that the default configuration
  is one user per group.