Beowulf/Cinnamon, default terminal is gnome-terminal and I've not noticed any issues using it (including a display from the xpra server over ssh on another machine), but I'm running it from an applet, so I don't see any messages.

However:

marjorie@grendel:~$ gnome-terminal
# watch_fast: "/org/gnome/terminal/legacy/" (establishing: 0, active: 0)
# unwatch_fast: "/org/gnome/terminal/legacy/" (active: 0, establishing: 1)
# watch_established: "/org/gnome/terminal/legacy/" (establishing: 0)

and child terminal opens OK.

marjorie@grendel:~$   

And then as sudo:

marjorie@grendel:~$ sudo gnome-terminal
# posix_spawn avoided (fd close requested) 
# watch_fast: "/org/gnome/terminal/legacy/" (establishing: 0, active: 0)
# unwatch_fast: "/org/gnome/terminal/legacy/" (active: 0, establishing: 1)
# watch_established: "/org/gnome/terminal/legacy/" (establishing: 0)

and child terminal opens OK as root in my home directory.

root@grendel:/home/marjorie#      

I don't have ash, nor xterm for that matter.

If I try that as root, I get the 'Error constructing proxy...' message and also 'Could not open X display' which is strange, because this system is set up to allow root to run graphical apps in a user session. My root can open lxterminal with no problems.

Seems like there's something weird about gnome-terminal, but I don't know what that is. We're not getting exactly the same behavior. I don't know where your ash command is coming from. I'm guessing you did not create a wrapper script or alias named 'gnome-terminal' that tries to run ash in gnome-terminal. I'm stumped.

Does the error message appear inside the terminal that you just opened, or is it in a notification window or other popup?

It is the first line in every terminal I open:

ash: 0: Can't open completion

GNOME-Terminal 3.30.2
Desktop: Cinnamon 3.8.8
Distro: Devuan GNU/Linux 3 (beowulf)

By right-clicking  under "edit" I get a window (launcher properties) with the following entries:

Name: Terminal
Command: gnome-terminal  (with a button "Browse" which opens a file manager)
Comment: Use the command line
there is a tickable box "Launch in Terminal? (not checked)

If I run  "gnome-terminal" (in a GNOME-Terminal) I get a new terminal (including :"ash: 0: Can't open completion" as first line).

If I stop that terminal with CTRL +D, the original terminal displays:

# Couldn't register with accessibility bus: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
# watch_fast: "/org/gnome/terminal/legacy/" (establishing: 0, active: 0)
# unwatch_fast: "/org/gnome/terminal/legacy/" (active: 0, establishing: 1)
# watch_established: "/org/gnome/terminal/legacy/" (establishing: 0)

All above as user!

If I switch to root and try to run "gnome-terminal"

I get this error (and NO new terminal-window!):

# Error constructing proxy for :1.98:/org/gnome/Terminal/Factory0: Verbindung ist geschlossen
# Failed to use specified server: Verbindung ist geschlossen
# Falling back to default server.
# Error constructing proxy for org.gnome.Terminal:/org/gnome/Terminal/Factory0: Verbindung ist geschlossen

"Verbindung ist geschlossen" means: "connection closed"

Thanks for your patience!

Also got two Beowulf VMs running in Virtual Box. One is based on an ASCII upgrade with Mate. Same setup as above, works like a charm w/o ash. The other one is a native Beowulf with Cinnamon. The I only have xterm, but that also works fine.

rolfie

I click on the "Terminal"-icon on my taskbar with my mouse

Do you happen to know what command that executes? If not, we should figure that out. What terminal is it, what desktop environment are you running? Maybe a right-click on that icon will let you see a list of Properties that will show the command.

Does the error message appear inside the terminal that you just opened, or is it in a notification window or other popup?

If you have a terminal that will let you run commands, run the command that the panel icon uses to open a terminal and see if it gives you any more information.

I do get an error message, when I open an console.

Please tell me exactly what you do to open a console.

Same with me!
I do get an error message, when I open an console.

I installed ascii from a netinstall iso. Upgraded to beowulf by replacing "ascii" in my sources.list

;-)
well I really don't know. It all started when I upgraded from ascii to beowulf.
Since then I got

bash: ash: command not found

whenever I open a console.
After installing "ash" I get

ash: 0: Can't open completion

Me neither.
Perhaps we ask the guys who develop ash/dash?
greetings

I'm not finding that error message on a web search. (Can't open completion)

bash-completion ist schon die neueste Version (1:2.8-6).

is already newest version
greetings

Have you got bash-completion installed?

I am not using the alias.

rolfie

ls -l *ash
lrwxrwxrwx 1 root root       4 Jan 17  2019 ash -> dash
-rwxr-xr-x 1 root root 1168776 Apr 18  2019 bash
-rwxr-xr-x 1 root root  121464 Jan 17  2019 dash
lrwxrwxrwx 1 root root       4 Apr 18  2019 rbash -> bash

NOW opening a console, I get:

ash: 0: Can't open completion 

To finish that

bash:ash: command not found

thing:
I just added an empty  "ash"-file in /bin.

Since then there are no more errors like

bash:ash: command not found

If anyone has an better idea or just can explain to me where that error message came/comes from;
you are very welcome!

I found no hint in .bashrc of any script or program that needs ash.
greetings

The error message is coming from bash - the command providing the error is the first word in the error message. You get 'command not found' if ash is not installed. If you're sure you installed it, then something weird is going on or you didn't notice when it got removed.

If you create an empty /bin/ash, you should then get 'permission denied' because it's not executable. If you make it executable, then the error messages go away, but of course it does nothing.

A few messages above, you said 'ash' gives you a root shell after aliasing 'su'. The prompt that you pasted is a bash prompt. The ash prompt is just # or $ for root or user, respectively.

Note: You can also get 'command not found' with the new default su setup if the command you're trying to run is in an sbin directory and you used 'su' instead of 'su -'. Your alias works around this.

bash:ash: command not found

thing:
I just added an empty  "ash"-file in /bin.

Since then there are no more errors like

bash:ash: command not found

If anyone has an better idea or just can explain to me where that error message came/comes from;
you are very welcome!

I found no hint in .bashrc of any script or program that needs ash.
greetings

"su" without argument

works fine

Yes .bashrc and .bash_aliases are those from root

GNU nano 3.2                     /root/.bashrc                                

# eval "`dircolors`"
# alias ls='ls $LS_OPTIONS'
# alias ll='ls $LS_OPTIONS -l'
# alias l='ls $LS_OPTIONS -lA'
#
# Some more alias to avoid making mistakes:
# alias rm='rm -i'
# alias cp='cp -i'
# alias mv='mv -i'
HISTSIZE=1000
HISTCONTROL=ignoredups:erasedups

GNU nano 3.2                  /root/.bash_aliases                             

alias su='su -'

But I overlooked three lines out commented in /etc/pam.d/su:

# This allows root to su without passwords (normal operation)
auth       sufficient pam_rootok.so

session       required   pam_env.so readenv=1 envfile=/etc/default/locale

session    optional   pam_mail.so nopen

session    required   pam_limits.so

greetings