First we connect to the server using ssh
Then we use sort and uniq commands to get the changed lines in both the files
ssh [email protected] -p 2220
cat passwords.old passwords.new | sort | uniq -u
cat passwords.old passwords.new prints the data of both the files in the given order
sort sorts it
uniq -u displays only the unique lines. Since one line is changed there are two output lines.
One from passwords.old, other from passwords.new.
Since we require the one from passwords.new, the second line is our flag
Flag - hga5tuuCLF6fFzUpnagiMN8ssu9LFrdg