Default Permissions on UNIX to Change

(If you do not log onto SSCC UNIX computers except for
using PINE or SSCMENU, you may safely ignore this message.
This message is intended for researchers who store files on
SSCC UNIX computers.)

Since UNIX was introduced at SSCC in the early 1990's, the
default permissions (except for e-mail) have been rw-r--r--
for files and rwxr-xr-x for directories (umask 022). With
these permissions, files on our system are readable by
everyone unless the owner makes the permissions more
restrictive. (For an explanation of UNIX permissions see

Some SSCC research groups would prefer that SSCC UNIX users
not be able to read others' files unless the owner has
explicitly given consent by changing the files' permissions
to make them readable. This is already the case on the
Windows network. Because of this, effective September 9, 2002
we will change the default permissions to rw-r----- for files
and rwxr-x--x for directories (umask 026). With these default
permissions, only the owner and group members will be able to
read files. (For a discussion of groups on UNIX, see

Technical Note: Leaving directories world executable makes it
easier to change a particular subdirectory to world readable,
such as the PUBLIC_web directory used for web pages.

Some implications that you should be aware of:

- This change will not affect any files or directories
already on our network; only files and directories
created after the change on September 9 will be affected.

- You can set your own default permissions by including a
umask command in your .cshrc file if you so desire. See for

- If you make web pages in your home directory space you
need to make sure your PUBLIC_web directory and all its
subdirectories and files are world-readable. See for instructions.

- To give someone access to a file by anonymous FTP, you
will need to make sure the file(s) and directory you
create for yourself under /usr/sysfolk/ftp/pub has
permissions set such that others can read the file(s) and
both read and execute the directory. Instructions are
provided in

It remains your responsibility to ensure that the permissions
are set appropriately for the your files, especially for
sensitive data. However, setting directory and file permissions
can be tricky. A simple mistake can make your files very
vulnerable so please don't hesitate to ask us for assistance --
just contact the Consultant (, 2-9917).

Nancy McDermott, Director
Social Science Computing Cooperative
University of Wisconsin - Madison
1180 Observatory Drive
Madison, WI 53706
(608) 262-3206