Author: MartinsM

In LightTable press Ctrl-Space to open Commands pane. Type “settings” and choose “Settings: User keymap”.
It will open keymap configuration. The following configuration adds PageUP and PageDown keyboard shortcuts to switch between opened files and Ctrl-/ shortcut to comment/uncomment current line.

;; User keymap
;; -----------------------------
;; Keymaps are stored as a set of diffs that are merged together together
;; to create the final set of keys. You can modify these diffs to either add
;; or subtract bindings.
;;
;; Like behaviors, keys are bound by tag. When objects with those tags are active
;; the key bindings are live. Keys can be bound to any number of Light Table commands,
;; allowing you the flexibility to execute multiple operations together. To see a list
;; of all the commands you can execute, start typing a word related to the thing you
;; want to do in between the square brackets (e.g. type "editor").

{:+ {:app {}

     :editor {"alt-w" [:editor.watch.watch-selection]
              "alt-shift-w" [:editor.watch.unwatch]
              "pmeta-/" [:toggle-comment-selection]}
     :tabs {"pmeta-pageup" [:tabs.prev]
            "pmeta-pagedown" [:tabs.next]
            }
     }}

To add line numbers or change color theme, you need to configure “User behaviors”. Press Ctrl-Space to open Commands pane, type “settings” and choose “Settings: User behaviors”.
Here is my configuration:

;; User behaviors
;; -----------------------------
;; Behaviors are stored as a set of diffs that are merged together
;; to create the final set of functionality that makes up Light Table. You can
;; modify these diffs to either add or subtract functionality.
;;
;; Behaviors are added to tags, objects with those tags then automatically gain
;; whatever logic the behavior imparts. To see a list of user-level behaviors,
;; start typing a word related to the functionality you want in between the square
;; brackets (e.g. "theme").

{:+ {
     ;; The app tag is kind of like global scope. You assign behaviors that affect
     ;; all of Light Table here
     :app [(:lt.objs.style/set-skin "dark")]

     ;; The editor tag is applied to all editors
     :editor [:lt.objs.editor/wrap
              :lt.objs.editor/line-numbers
              (:lt.objs.style/font-settings "" "12" "1.2")
              (:lt.objs.style/set-theme "monokai")]

     ;; Here we can add behaviors to just clojure editors
     :editor.clojure [(:lt.objs.langs.clj/print-length 1000)]}

 ;; You can use the subtract key to remove behavior that may get added by
 ;; another diff
 :- {:app []}}