You can remove the minimal bash like line editing is supported message by opening the .bashrc file in your home directory and commenting out the following line:
enable bash completion in interactive shells
#if ! shopt -oq posix; then
if [ -f /usr/share/bash-completion/bash_completion ]; then
. /usr/share/bash-completion/bash_completion
elif [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fi
#fi
To do this, open the .bashrc file in a text editor and add a # at the beginning of the line. Save the file and exit the text editor.