I've noticed that a lot of the packages I've been installing on my Ubuntu machine has this "d" at the end. Googling it doesn't give me any answers that I can find.
For example:
FTP server - Package called: pure-ftpd
TFTP server - Package called: atftpd
SSH server - Package called: sshd
What's up with this "d"?
d is for demon or daemon in this case.
Those packages are the background processes that handle the various connections (FTP, TFTP, SSH) mentioned.
As a hint, the name of the package ("__ server") indicates you're likely going to need a background process running to provide that service.
And here's the Wikipedia quote on daemon
In multitasking computer operating systems, a daemon (/ˈdeɪmən/ or /ˈdiːmən/)[1] is a computer program that runs as a background process, rather than being under the direct control of an interactive user. Traditionally daemon names end with the letter d: for example, syslogd is the daemon that implements the system logging facility and sshd is a daemon that services incoming SSH connections.
In multitasking computer operating systems, a daemon (/ˈdeɪmən/ or /ˈdiːmən/) is a computer program that runs as a background process, rather than being under the direct control of an interactive user. Traditionally daemon names end with the letter d: for example, syslogd is the daemon that implements the system logging facility and sshd is a daemon that services incoming SSH connections.
[...]
The term was coined by the programmers of MIT's Project MAC. They took the name from Maxwell's demon, an imaginary being from a famous thought experiment that constantly works in the background, sorting molecules.
