diff --git a/src/atoss_cli/cli.clj b/src/atoss_cli/cli.clj
new file mode 100644
index 0000000..3b1a189
--- /dev/null
+++ b/src/atoss_cli/cli.clj
@@ -0,0 +1,48 @@
+(ns atoss-cli.cli
+  (:require [atoss-cli.atoss :refer [valid-day-codes]])
+  (:import (java.text SimpleDateFormat)
+           (java.util Date)))
+
+(def today-date (.format
+                 (SimpleDateFormat. "dd.MM.yyyy")
+                 (new Date)))
+
+(def desc "ATOSS CLI by Platogo Interactive Entertainment Gmbh.
+Work seamlessly with ATOSS time sheets.")
+
+(def help-header "
+\033[1;37mUSAGE\u001b[0m
+  atoss-cli <command> [args]
+
+\033[1;37mCOMMANDS\u001b[0m
+  log:       Log time pair for today or a specific date
+  view:      View month overview of logged time")
+
+(def options
+  ;; An option with a required argument
+  [["-d" "--date DATE" "Date in the format DD.MM.YYYY"
+    :default today-date] ;; FIXME: Add validation
+   ["-c" "--day-code CODE" "Valid ATOSS day code (e.g. wh for WFH) can also be left blank."
+    :default nil
+    :validate [#(contains? valid-day-codes %) "Must be a valid ATOSS time code."]]
+   ["-s" "--start-time TIME" "Work start time in the format HH:MM"
+    :default "9:00"]
+   ["-e" "--end-time TIME" "Work end time in the format HH:MM"
+    :default "17:00"]
+   ;; A non-idempotent option (:default is applied first)
+   ["-v" nil "Verbosity level"
+    :id :verbosity
+    :default 0
+    :update-fn inc]
+   ;; A boolean option defaulting to nil
+   ["-h" "--help" "Show this help printout."
+    :default false]])
+
+(defn print-help
+  [args-summary]
+  (print desc)
+  (newline)
+  (print help-header)
+  (newline)
+  (newline)
+  (print args-summary))
diff --git a/src/atoss_cli/core.clj b/src/atoss_cli/core.clj
index 90fbf2c..e81320e 100644
--- a/src/atoss_cli/core.clj
+++ b/src/atoss_cli/core.clj
@@ -1,54 +1,11 @@
 (ns atoss-cli.core
   "Entrypoint module for the ATOSS CLI."
   (:require [clojure.tools.cli :refer [parse-opts]]
-            [atoss-cli.atoss :as atoss])
-  (:import (java.util Date Collection) [java.text SimpleDateFormat])
+            [atoss-cli.atoss :as atoss]
+            [atoss-cli.cli :as cli])
+  (:import (java.util Collection))
   (:gen-class))
 
-(def today-date (.format
-                 (SimpleDateFormat. "dd.MM.yyyy")
-                 (new Date)))
-
-(def desc "ATOSS CLI by Platogo Interactive Entertainment Gmbh.
-Work seamlessly with ATOSS time sheets.")
-
-(def help-header "
-\033[1;37mUSAGE\u001b[0m
-  atoss-cli <command> [args]
-
-\033[1;37mCOMMANDS\u001b[0m
-  log:       Log time pair for today or a specific date
-  view:      View month overview of logged time")
-
-(def cli-options
-  ;; An option with a required argument
-  [["-d" "--date DATE" "Date in the format DD.MM.YYYY"
-    :default today-date] ;; FIXME: Add validation
-   ["-c" "--day-code CODE" "Valid ATOSS day code (e.g. wh for WFH) can also be left blank."
-    :default nil
-    :validate [#(contains? atoss/valid-day-codes %) "Must be a valid ATOSS time code."]]
-   ["-s" "--start-time TIME" "Work start time in the format HH:MM"
-    :default "9:00"]
-   ["-e" "--end-time TIME" "Work end time in the format HH:MM"
-    :default "17:00"]
-   ;; A non-idempotent option (:default is applied first)
-   ["-v" nil "Verbosity level"
-    :id :verbosity
-    :default 0
-    :update-fn inc]
-   ;; A boolean option defaulting to nil
-   ["-h" "--help" "Show this help printout."
-    :default false]])
-
-(defn -print-help
-  [args-summary]
-  (print desc)
-  (newline)
-  (print help-header)
-  (newline)
-  (newline)
-  (print args-summary))
-
 (defn log-time
   "Log a time pair for a given day."
   [{opts :options}]
@@ -84,10 +41,10 @@ Work seamlessly with ATOSS time sheets.")
   (let [{^Collection arguments :arguments
          summary :summary,
          options :options,
-         :as opts} (parse-opts args cli-options)]
+         :as opts} (parse-opts args cli/options)]
     (cond
-      (options :help) (-print-help summary)
+      (options :help) (cli/print-help summary)
       (= (first arguments) "view") (show-month-overview)
       (= (first arguments) "log") (log-time opts)
-      :else (-print-help summary))
+      :else (cli/print-help summary))
     (flush)))