optimized _apply_theme() to launch background jobs straight from _apply_configuration()

tmux doesn't share jobs between clients, and when multiple clients are attached
the _load_avg(), _uptime() and _battery_bar() jobs get spawned once per client
attached, which is wasteful

.tmux.conf

@@ -188,9 +188,6 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #   fi
 # fi
 #
-# __newline='
-# '
-#
 # _uname_s=$(uname -s)
 #
 # _is_enabled() {
@@ -350,25 +347,12 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #     return
 #   fi
 #
-#   variables=$(tmux  show -gqv '@battery_bar_symbol_full' \;\
-#                     show -gqv '@battery_bar_symbol_empty' \;\
-#                     show -gqv '@battery_bar_length' \;\
-#                     show -gqv '@battery_bar_palette' \;\
-#                     show -gqv '@battery_hbar_palette' \;\
-#                     show -gqv '@battery_vbar_palette' \;\
-#                     show -gqv '@battery_status_charging' \;\
-#                     show -gqv '@battery_status_discharging')
-#   # shellcheck disable=SC2086
-#   { set -f; IFS="$__newline"; set -- $variables; unset IFS; set +f; }
-#
 #   battery_bar_symbol_full=$1
 #   battery_bar_symbol_empty=$2
 #   battery_bar_length=$3
 #   battery_bar_palette=$4
 #   battery_hbar_palette=$5
 #   battery_vbar_palette=$6
-#   battery_status_charging=$7
-#   battery_status_discharging=$8
 #
 #   if [ x"$battery_bar_length" = x"auto" ]; then
 #     columns=$(tmux -q display -p '#{client_width}' 2> /dev/null || echo 80)
@@ -379,12 +363,6 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #     fi
 #   fi
 #
-#   if [ x"$discharging" = x"true" ]; then
-#     battery_status="$battery_status_discharging"
-#   else
-#     battery_status="$battery_status_charging"
-#   fi
-#
 #   if echo "$battery_bar_palette" | grep -q -E '^heat|gradient(,[#a-z0-9]{7,9})?$'; then
 #     # shellcheck disable=SC2086
 #     { set -f; IFS=,; set -- $battery_bar_palette; unset IFS; set +f; }
@@ -1092,14 +1070,14 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #
 #   # -- variables
 #
-#   tmux_conf_battery_bar_symbol_full=${tmux_conf_battery_bar_symbol_full:-◼}
+#   tmux_conf_battery_bar_symbol_full=$(_decode_unicode_escapes "${tmux_conf_battery_bar_symbol_full:-◼}")
-#   tmux_conf_battery_bar_symbol_empty=${tmux_conf_battery_bar_symbol_empty:-◻}
+#   tmux_conf_battery_bar_symbol_empty=$(_decode_unicode_escapes "${tmux_conf_battery_bar_symbol_empty:-◻}")
 #   tmux_conf_battery_bar_length=${tmux_conf_battery_bar_length:-auto}
 #   tmux_conf_battery_bar_palette=${tmux_conf_battery_bar_palette:-gradient}
-#   tmux_conf_battery_hbar_palette=${tmux_conf_battery_hbar_palette:-gradient} # red, orange, green
+#   tmux_conf_battery_hbar_palette=${tmux_conf_battery_hbar_palette:-gradient}                                    # red, orange, green
-#   tmux_conf_battery_vbar_palette=${tmux_conf_battery_vbar_palette:-gradient} # red, orange, green
+#   tmux_conf_battery_vbar_palette=${tmux_conf_battery_vbar_palette:-gradient}                                    # red, orange, green
-#   tmux_conf_battery_status_charging=${tmux_conf_battery_status_charging:-↑}       # U+2191
+#   tmux_conf_battery_status_charging=$(_decode_unicode_escapes "${tmux_conf_battery_status_charging:-↑}")        # U+2191
-#   tmux_conf_battery_status_discharging=${tmux_conf_battery_status_discharging:-↓} # U+2193
+#   tmux_conf_battery_status_discharging=$(_decode_unicode_escapes "${tmux_conf_battery_status_discharging:-↓}")  # U+2193
 #
 #   case "$status_left $status_right" in
 #     *'#{battery_status}'*|*'#{battery_bar}'*|*'#{battery_hbar}'*|*'#{battery_vbar}'*|*'#{battery_percentage}'*)
@@ -1116,8 +1094,9 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #         -e 's/#\{(\?)?battery_status/#\{\1@battery_status/g' \
 #         -e 's/#\{(\?)?battery_percentage/#\{\1@battery_percentage/g')
 #       interval=60
-#       pkill -f 'cut -c3- ~/\.tmux\.conf \| sh -s _battery' || true
+#       pkill -f 'cut -c3- ~/\.tmux\.conf \| sh -s _battery_bar' || true
-#       status_right="#(printf '\n'; nice cut -c3- ~/.tmux.conf | sh -s _battery_status \"$tmux_conf_battery_status_charging\" \"$tmux_conf_battery_status_discharging\")#(printf '\n'; while [ \$(tmux display -p '##{session_attached}') -gt 0 ]; do nice cut -c3- ~/.tmux.conf | sh -s _battery_bar; sleep $interval; done)$status_right"
+#       tmux run -b "trap 'exit 0' TERM; while :; do nice cut -c3- ~/.tmux.conf | sh -s _battery_bar \"$tmux_conf_battery_bar_symbol_full\" \"$tmux_conf_battery_bar_symbol_empty\" \"$tmux_conf_battery_bar_length\" \"$tmux_conf_battery_bar_palette\" \"$tmux_conf_battery_hbar_palette\" \"$tmux_conf_battery_vbar_palette\"; sleep $interval; done"
+#       status_right="#(printf '\n'; nice cut -c3- ~/.tmux.conf | sh -s _battery_status \"$tmux_conf_battery_status_charging\" \"$tmux_conf_battery_status_discharging\")$status_right"
 #       ;;
 #   esac
 #
@@ -1159,7 +1138,7 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #           ;;
 #       esac
 #       pkill -f 'cut -c3- ~/\.tmux\.conf \| sh -s _uptime' || true
-#       status_right="#(printf '\n'; while [ \$(tmux display -p '##{session_attached}') -gt 0 ]; do nice cut -c3- ~/.tmux.conf | sh -s _uptime; sleep $interval; done)$status_right"
+#       tmux run -b "trap 'exit 0' TERM; while :; do nice cut -c3- ~/.tmux.conf | sh -s _uptime; sleep $interval; done"
 #       ;;
 #   esac
 #
@@ -1171,7 +1150,7 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #         -e 's/#\{(\?)?loadavg/#\{\1@loadavg/g')
 #       interval=$(tmux show -gv status-interval)
 #       pkill -f 'cut -c3- ~/\.tmux\.conf \| sh -s _loadavg' || true
-#       status_right="#(printf '\n'; while [ \$(tmux display -p '##{session_attached}') -gt 0 ]; do nice cut -c3- ~/.tmux.conf | sh -s _loadavg; sleep $interval; done)$status_right"
+#       tmux run -b "trap 'exit 0' TERM; while :; do nice cut -c3- ~/.tmux.conf | sh -s _loadavg; sleep $interval; done"
 #       ;;
 #   esac
 #
@@ -1197,12 +1176,6 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #        setw -g window-status-activity-style "fg=$tmux_conf_theme_window_status_activity_fg,bg=$tmux_conf_theme_window_status_activity_bg,$tmux_conf_theme_window_status_activity_attr" \;\
 #        setw -g window-status-bell-style "fg=$tmux_conf_theme_window_status_bell_fg,bg=$tmux_conf_theme_window_status_bell_bg,$tmux_conf_theme_window_status_bell_attr" \;\
 #        setw -g window-status-last-style "fg=$tmux_conf_theme_window_status_last_fg,bg=$tmux_conf_theme_window_status_last_bg,$tmux_conf_theme_window_status_last_attr" \;\
-#        set -g '@battery_bar_symbol_full' "$(_decode_unicode_escapes "$tmux_conf_battery_bar_symbol_full")" \;\
-#        set -g '@battery_bar_symbol_empty' "$(_decode_unicode_escapes "$tmux_conf_battery_bar_symbol_empty")" \;\
-#        set -g '@battery_bar_length' "$tmux_conf_battery_bar_length" \;\
-#        set -g '@battery_bar_palette' "$tmux_conf_battery_bar_palette" \;\
-#        set -g '@battery_hbar_palette' "$tmux_conf_battery_hbar_palette" \;\
-#        set -g '@battery_vbar_palette' "$tmux_conf_battery_vbar_palette" \;\
 #        set -g status-left-length 1000 \; set -g status-left "$(_decode_unicode_escapes "$status_left")" \;\
 #        set -g status-right-length 1000 \; set -g status-right "$(_decode_unicode_escapes "$status_right")" \;\
 #        setw -g clock-mode-colour "$tmux_conf_theme_clock_colour" \;\