The XLSperl command line program provides a very convenient way to process Excel spreadsheets using a similar approach to standard Perl one liners.
An excellent idea and implementation.
XLSperl basically allows you to process a binary Excel file as if it was a text file using standard Perl syntax. For example you can do things like the following:
XLSperl -lne 'print if /foo/ and $COL eq "C"' file.xls