Writing to another file

Hi,

I have 2 unix files. I have to write all the information in the 2nd file to the 1st file at the end of the 1st file. What is the command for that.
Pl tell me ASAP.

Thanks

cat filename2>>filename1

Pl tell me the command to use within the VI Editor.

thanks

If 1st file is being edited then
M+g (go to the end of file)
:r 2ndfilename

If 2nd file was opened in vi then
:!cat 2ndfilename >>1stfilename