I get a .csv file, in which the last line has the footer value
**WOR_FOOTER_20160705100007_000000010_WOR_896312_20160705_100007.csv**--This is footer.
sed -i.bak '$s/WOR/VWOR/g' file
should do it.
$picks the last line.
s/WOR/VWOR/gdoes the global substitution.
-istands for inplace edit which means directly modify the file. A backup with
.bakwill be auto-created.
If your shell doesn't support inplace edit do
sed '$s/WOR/VWOR/g' file >tempfile && mv tempfile file