scp works, but you can also use
rsync -e 'ssh -p <port>' <user>@<computer1address>:Desktop/test1.txt ~/Downloads/
Most of the time
rsync is a drop-in replacement for
scp, i.e. with most
scp commands you can just replace
rsync and it will work the same way. The only reason that isn't true for your case is that
rsync doesn't have a
-p option to specify the port (well, it does, but it only applies when rsync connects through its own native protocol, not over ssh). So you need to tell it to use an alternate ssh command that includes the port.
If your ssh server uses the standard port, or if you have the port configured in
~/.ssh/config (in either case, this means you don't need to use the
-p option when connecting with ssh), then you can just run
rsync <user>@<computer1address>:Desktop/test1.txt ~/Downloads/
In general, I prefer
scp because it has many more options, and because if you're transferring a large number of files, rsync has the sense to skip ones that already exist on the destination system, cutting down on the amount of data that has to be transferred.