easy shell scripting question

I've made with the help of people here this script to filter the ssh attempts:

#!/bin/sh
cat /var/log/messages | grep "authentication failure;" | gawk -F: '{ print $4 }' > /tmp/ssh.txt
sort /tmp/ssh.txt | uniq > /tmp/sshfinal.txt
cat /tmp/sshfinal.txt | gawk -F"rhost=" '{ split($2, a, " |\r\n"); print a[1]; }' | uniq > /tmp/sshfinal.txt

i've added this line to get it via email after a cron setup.

echo -e "Subject:Firewall\nFrom:Server <senderemail\>\n"`cat /tmp/sshfinal.txt` | /usr/sbin/sendmail myemail

The sshfinal.txt file looks like this:
195.97.43.147
201.218.205.164
202.103.69.69
203.146.140.96
217.65.24.148
218.239.223.223
218.249.174.24
222.90.232.199

But ofcourse when I receive the email its like this :
195.97.43.147 201.218.205.164 202.103.69.69 203.146.140.96 217.65.24.148 218.239.223.223

it may sounds stupid but how can I change that ?

I know i could do that if i would use \n at the end of each ip in the sshfinal.txt file, but the file is generated by the script each time so I dont know how to do that.