Through the magic that is searching :)  [excel diff] excel diff  [ddg://perl excel diff sheet] perl excel diff sheet ->
xlsmerge - Merge worksheets from different Excel files into one Workbook
Perl script to Diff 2 Excel sheets - nntp.perl.org
Comparing two Excel spread sheets
https://metacpan.org/release/Text-CSV_XS /examples/csvdiff
http://search.cpan.org/dist/Test-Differences/MANIFEST
compare two Excel spreadsheets
Index of Spreadsheet FAQs
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compare two excel sheets - Stack Overflow
compare excel sheets - Perl