Linux – How to start an xterm from Nautilus, running in the folder I’m viewing

Caleb is right in his comment. xterm is fairly old and you should consider switching to urxvt -- at least the 256 and utf-8 enabled version, refer to your package manager to install the right one.

I have an identical set up to yours -- awesome WM, vim, urxvt, tmux/screen -- and they all work well with 256 colours and utf-8. I have set TERM to xterm-256color in case you need to set this manually.

Hum... After your edit, can you check if the vim colour theme is properly defined for terminals?

I've found solution relying heavily on tmux. Since tmux is working independently of the shell and prevails even after closing the windows, one can prepare a tmux session and then attach to it. The thing won't instantly exit, since the attachment command does not return unless you exit it.

This and the fact that you can name and search a session yields the following Nautilus-Script:

#!/bin/bash
# nautilus script to start files in nvim under a tmux session
# place this script into ~/.local/share/nautilus/scripts/nvimOpen.sh
# presented without warranty by mike aka curvi

# nvim running in another session? -
# TODO tmux rename-session -t $whaever nvim

# Tmux session 'nvim' is running neovim always!
if tmux has-session -t nvim ; then
  # test if it is open and split it
  for selected_file in $NAUTILUS_SCRIPT_SELECTED_FILE_PATHS ; do
    tmux send-keys -t nvim Escape # change to normal mode
    tmux send-keys -t nvim ";vsp $selected_file" Enter # open file in vsplit
  done
else
  # or start it up freshly!
  tmux new-session -d -s nvim ;
  tmux send-keys -t nvim "nvim -O $NAUTILUS_SCRIPT_SELECTED_FILE_PATHS" Enter
  tmux send-keys -t nvim Escape # change to normal mode
fi
# after the tmux session is prepared - attach to it in gnome-terminal!
gnome-terminal -e "tmux attach-session -d -t nvim"

Bonus: since I send the keys, instead of issueing the commands directly they appear in the terminals history, like expected!

Attention: my nvim/init.vim contains a remapping of ; to :, which means, that in order to run one has to check the sent keys for "regular" vim/neovim settings!