Shell script to copy files

Question

If there exist a directory,

/backup/ And the files in it are a.gz b.gz c.gz

And another directory /backup-directorybackup And the files in it are a.gz

I need a shells script to compare two directories if the files are present then ignore it and if the filesare not present copy it to the destination directory

Thanks..

Answer 1

"rsync" command has it all

Answer 2

rsync -a /backup/ /backup-directorybackup/