splitting into more modular structure

tmux.conf

@@ -1,5 +1,5 @@
-if-shell "uname | grep -q Darwin" "set -g default-command \"reattach-to-user-namespace -l $SHELL\""
-set -g default-terminal "screen-256color"
+if-shell "command -v reattach-to-user-namespace" "set -g default-command \"reattach-to-user-namespace -l $SHELL\""
+set -g default-terminal "tmux-256color"
 run "~/.dotfiles/tmux.sh"
 set -g base-index 1
 set -g set-titles on
@@ -15,6 +15,8 @@ setw -g automatic-rename on
 setw -g monitor-activity on
 setw -g aggressive-resize on
 
+set -g mouse on
+
 unbind C-a
 unbind C-b