converting excel file to text file in unix

[Oh Edwin <alienzzz85 gmail com>]

I am currently using an unix environment. just to double confirm that
gnumeric can convert all my excel file (.xls) into text file(.txt)? my
job are for batch processing thus i hope it would be with least human
intervention. is it possible?
is there any other tools currently on the market that are able to do that?

sorry to waste your time.
thanks :)