add commands for osx

lib/utils.sh

@@ -1,3 +1,5 @@
+#!/bin/sh
+
 # http://stackoverflow.com/a/1369211/183097
 copy_function () {
   declare -F $1 > /dev/null || return 1
@@ -6,4 +8,12 @@ copy_function () {
 
 is_function () {
   [ "`type -t $1`" == 'function' ]
-}
+}
+
+OS_TYPE=$(case "$OSTYPE" in
+  (solaris*) echo solaris;;
+  (darwin*)  echo osx;;
+  (linux*)   echo linux;;
+  (bsd*)     echo bsd;;
+  (*)        echo unknown;;
+esac)