printf in bash sometimes prints new line, can't figure out why - bash

Question

if i have a file with below contents:
127.0.0.1
127.0.0.2
127.0.0.3
8.8.8.8
127.0.0.4
and run this command to quickly test SSH connection success or failure:
while read host
do
ssh -n -q -o BatchMode=yes -o ConnectTimeout=5 $host "echo 2>&1" && \
printf "%-15s%-45s%s" `id -un` $host "SSH_OK" || \
printf "%-15s%-45s%s" `id -un` $host "SSH_BAD"
done <host_list
I get:
myname 127.0.0.1 SSH_OK
myname 127.0.0.2 SSH_OK
myname 127.0.0.3 SSH_OKmyname 8.8.8.8 SSH_BAD
myname 127.0.0.4 SSH_OK[myname#server ~]$
As you can see, it looks nasty because it doesn't print a newine for the SSH_BAD output or the last line so bash prompt is tagged to end of last check.
I can fix this by adding a \n to the prinf but then i have double spaces on everything except for the BAD line.
Can someone tell me please where is printf getting the newline from when i don't specify one, and why it prints one for the SSH_OK lines but not the SSH_BAD lines.
Is there a good/easy way to fix this?
thank you
fLo

Answer 1

The newlines are coming from echo 2>&1 that you're running on the remote system. When the ssh is successful, this command executes, and you get a newline printed before the printf. When the ssh fails, the command doesn't run, so you get no newline before the printf.
I suggest you use a command that doesn't display anything, and then put \n in both printf lines:
while read host
do
ssh -n -q -o BatchMode=yes -o ConnectTimeout=5 $host "true" && \
printf "%-15s%-45s%s\n" `id -un` $host "SSH_OK" || \
printf "%-15s%-45s%s\n" `id -un` $host "SSH_BAD"
done <host_list