$ xlscat -c old.xls
"Student ID",Name,Test,Grade
1,"Tom Hanks",Math,F
2,"Angelina Jolie",Biology,B
3,"David Gilmour",Music,A
$ xlscat -c old.xls >old.csv
$ xlscat -c new.xls
"Student ID",Name,Test,Grade
1,"Tom Hanks",Math,B
2,"Angelina Jolie",Biology,B
3,"David Gilmour",Music,A
4,Bono,Singing,"F- (EPIC FAIL)"
$ xlscat -c new.xls >new.csv
$ csvdiff old.csv new.csv
# csvdiff   < old.csv    > new.csv
< 1,"Tom Hanks",Math,"F"
> 1,"Tom Hanks",Math,"B"
+ 4,Bono,Singing,"F- (EPIC FAIL)"