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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"?

noblerare
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    This question appears to be off-topic because it is about something that is not a subjective question about programming. – user16764 Aug 20 '13 at 17:21
  • @user16764 per my reading of [about] page, being _subjective_ is not a mandatory requirement for the question to be on-topic: "*conceptual* questions..." – gnat Aug 20 '13 at 17:40
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    It belongs to askubuntu SE o Unix-Linux SE – Tulains Córdova Sep 20 '13 at 01:00

2 Answers2

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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.

  • It should be noted, that the actual binaries also have this `d` in their name. – Jan Hudec Aug 20 '13 at 15:47
  • @JanHudec - that's a good point. The packages often reflect the name of the primary binary that would be used. –  Aug 20 '13 at 15:49
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Daemon:

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.

Michael Borgwardt
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