IF you want to take back up or transfer data of one or more folder, you can do it using command rsync.
In this case a folder of which you want to take back up is called as source directory and folder where you are taking the backup is called as destination folder.

Let us assume that you have two folders. First one is backup_source and another is backup_destination.
backup_source is a folder of which you have to take backup into folder backup_destination.
run the simple command to accomplish the task.
rsync -ave backup_source/ backup_destination/
This is simple way from which you can take backup.
Now let us understand the options use in command
1)-a, –archive archive mode; same as -rlptgoD (no -H)
Instead of using several options like -rlptgoD, you can use just a option which is equivalent to the said options.
-r, –recursive recurse into directories
-l, –links copy symlinks as symlinks
-p, –perms preserve permissions
-t, –times preserve times
-g, –group preserve group
-o, –owner preserve owner (super-user only)
-D same as –devices –specials
2)-v, –verbose increase verbosity
3)-e, –rsh=COMMAND specify the remote shell to use

If you want to take backup from another machine over secure shell
use following command.
rsync -ave ssh username@anothermachine/backup_source/ backup_destination