Inserting a blank line at the end of a .txt file?

Hi there,

I am having this problem:
a) I am uploading a txt file from windows (notepad) with some Gaussian 09 command lines;
b) Gaussian needs in certain command files, that those files have a blank line at the end of the file!
c) I open the command file with vi and no blank line at the of the file!
d) Gaussian gives an error due to that missing blank line!

How can I finish my command file with a blank line?

Thanks in advance! Best,

Luis

Try:

echo >> file

It worked in perfection! Thank you very much!