UNIX has the ability to refer to a number of files and/or directories using ``wildcards''. The wildcard for a single character is ``?'' and for any number of characters is ``*''. For example, to refer to all the files beginning with ``ex'' in the directory:
/usr/local/pmag1.0/datafiles,
we use:
/usr/local/pmag1.0/datafiles/ex*.
To refer only to those from Chapter 1, we use:
/usr/local/pmag1.0/datafiles/ex1.? . [an error occurred while processing this directive] [an error occurred while processing this directive]