"clear" command in GNOME terminal returns "terminals database is inaccessible"

Solution 1:

This can happen a lot with terminal multiplexers (screen, tmux, etc...)

If if you are running one of those, make sure that your TERM is set to screen-256color for the broadest support. I've run into issues in BSD, Linux, Multiple x window managers, etc... from this.

Check for set -g default-terminal screen-256color in ~/.tmux.conf or term screen-256color in ~/.screenrc as TERM is changed by your multiplexer when you load it.

If echo $TERM already says screen-256color try this:

TERM='xterm' clear. If that works, then your terminal emulator doesn't support the standard multiplexer configuration. You might need to add something special for that particular terminal emulator in your bashrc/bash_profile.

Keep in mind that this problem is related to your tool selection and configuration. Ubuntu attempts to choose defaults that work well with other defaults so that everything 'just works'.