logname: no login name about dietpi

[Joulinar]

If I'm not mistaken, logname expecting a tty session which ssh normally does not provide.

[rlesac]

I could not install various software I needed to run on the Raspberry pi because of it.
I got a hint that it is SSH related and switched from Dropbear to OpenSSH, and it's now working.

[MichaIng]

logname returns the name of the user logged in based in /var/run/utmp, ignoring sudo/runuser and possible subshells. Dropbear seems to not create that entry, similar to how it does not use all PAM features etc. One can check the w command for registered login sessions.

To be true, I never heard of this command before, but $USER, $LOGNAME variables or whoami command. As you say "various software", which software exactly requires the logname command to be installed?

[rlesac]

logname returns the name of the user logged in based in /var/run/utmp, ignoring sudo/runuser and possible subshells. Dropbear seems to not create that entry, similar to how it does not use all PAM features etc. One can check the w command for registered login sessions.

To be true, I never heard of this command before, but $USER, $LOGNAME variables or whoami command. As you say "various software", which software exactly requires the logname command to be installed?

It's https://github.com/Stefal/rtkbase

[MichaIng]

I see. It uses bash for the installer, and suggests to run it with sudo, so a failsafe replacement (or fallback) for logname would be $SUDO_USER, else $USER variables, which is assured to be set in bash, hence also makes this "empty value" check obsolete.