bashrc/.bashrc

#!/usr/bin/env bash
# ~/.bashrc: executed by bash(1) for non-login shells.

# If not running interactively, don't do anything
case $- in
  *i*) ;;
  *) return ;;
esac

chmod 700 ~/.bashrc.d
chmod 600 ~/.bashrc ~/.bashrc.d/*

# check if we are already in a Tmux session or open/attach the default one
if [[ "${TERM-}" != tmux* ]] && [[ -z "${TMUX}" ]] && [[ -z "${SSH_CONNECTION}" ]] && command -v tmux 1> /dev/null; then
  # open/attach the local default Tmux session
  systemd-run -q --scope --user tmux new-session -A -s local && exit
elif [[ -z "${TMUX}" ]] && [[ -n "${SSH_CONNECTION}" ]] && command -v tmux 1> /dev/null; then
  # open/attach the SSH default Tmux session
  systemd-run -q --scope --user tmux new-session -A -s ssh && exit
fi

# if Tmux is not installed or if we are inside a Tmux session continue the sourcing
for file in ~/.bashrc.d/*.bashrc;
do
  source "${file}"
done