diff --git a/.ipynb_checkpoints/timeit_tests-checkpoint.ipynb b/.ipynb_checkpoints/timeit_tests-checkpoint.ipynb
index f9b9ce7..0e7bd18 100644
--- a/.ipynb_checkpoints/timeit_tests-checkpoint.ipynb
+++ b/.ipynb_checkpoints/timeit_tests-checkpoint.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:faa7cde23cd1ec6598ad386b44eabe2d06ad86d6bdd84c7d999dd174c7df48a6"
+  "signature": "sha256:c5925e90d7a8c3e6fb36f4e3ca876248f4ba69529367d87b73ef3da2b5415766"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -64,7 +64,8 @@
       "    - [Creating lists using conditional statements](#create_cond_list)\n",
       "- [Dictionary operations](#dict_ops) \n",
       "    - [Adding elements to a dictionary](#adding_dict_elements)\n",
-      "- [Comprehensions vs. for-loops](#comprehensions)"
+      "- [Comprehensions vs. for-loops](#comprehensions)\n",
+      "- [Copying files by searching directory trees](#find_copy)"
      ]
     },
     {
@@ -1023,6 +1024,14 @@
       "# Comprehesions vs. for-loops"
      ]
     },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Comprehensions are not only shorter and prettier than ye goode olde for-loop,  \n",
+      "but they are also up to ~1.2x faster."
+     ]
+    },
     {
      "cell_type": "code",
      "collapsed": false,
@@ -1126,7 +1135,7 @@
      "language": "python",
      "metadata": {},
      "outputs": [],
-     "prompt_number": 11
+     "prompt_number": 23
     },
     {
      "cell_type": "code",
@@ -1138,7 +1147,7 @@
      "language": "python",
      "metadata": {},
      "outputs": [],
-     "prompt_number": 12
+     "prompt_number": 24
     },
     {
      "cell_type": "code",
@@ -1154,8 +1163,8 @@
        "output_type": "stream",
        "stream": "stdout",
        "text": [
-        "10000 loops, best of 3: 130 \u00b5s per loop\n",
-        "10000 loops, best of 3: 114 \u00b5s per loop"
+        "10000 loops, best of 3: 129 \u00b5s per loop\n",
+        "10000 loops, best of 3: 111 \u00b5s per loop"
        ]
       },
       {
@@ -1166,7 +1175,7 @@
        ]
       }
      ],
-     "prompt_number": 14
+     "prompt_number": 25
     },
     {
      "cell_type": "markdown",
@@ -1189,7 +1198,7 @@
      "language": "python",
      "metadata": {},
      "outputs": [],
-     "prompt_number": 15
+     "prompt_number": 26
     },
     {
      "cell_type": "code",
@@ -1201,7 +1210,7 @@
      "language": "python",
      "metadata": {},
      "outputs": [],
-     "prompt_number": 17
+     "prompt_number": 27
     },
     {
      "cell_type": "code",
@@ -1217,8 +1226,8 @@
        "output_type": "stream",
        "stream": "stdout",
        "text": [
-        "10000 loops, best of 3: 120 \u00b5s per loop\n",
-        "10000 loops, best of 3: 118 \u00b5s per loop"
+        "10000 loops, best of 3: 121 \u00b5s per loop\n",
+        "10000 loops, best of 3: 127 \u00b5s per loop"
        ]
       },
       {
@@ -1229,15 +1238,145 @@
        ]
       }
      ],
-     "prompt_number": 18
+     "prompt_number": 28
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "<a name=\"find_copy\"></a>\n",
+      "<br>\n",
+      "<br>"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "# Copying files by searching directory trees"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Executing `Unix`/`Linux` shell commands:"
+     ]
     },
     {
      "cell_type": "code",
      "collapsed": false,
-     "input": [],
+     "input": [
+      "import subprocess\n",
+      "\n",
+      "def subprocess_findcopy(path, search_str, dest):    \n",
+      "    query = 'find %s -name \"%s\" -exec cp {}\" %s \\;' %(path, search_str, dest)\n",
+      "    subprocess.call(query, shell=True)\n",
+      "    return  "
+     ],
      "language": "python",
      "metadata": {},
-     "outputs": []
+     "outputs": [],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Using Python's `os.walk()` to search the directory tree recursively and matching patterns via `fnmatch.filter()`"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "import shutil\n",
+      "import os\n",
+      "import fnmatch\n",
+      "\n",
+      "def walk_findcopy(path, search_str, dest):\n",
+      "    for path, subdirs, files in os.walk(path):\n",
+      "        for name in fnmatch.filter(files, search_str):\n",
+      "            shutil.copy(os.path.join(path,name), dest)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "import timeit\n",
+      "\n",
+      "print('small tree')\n",
+      "inpath = '/Users/sebastian/Desktop/testdir_in'\n",
+      "outpath = '/Users/sebastian/Desktop/testdir_out'\n",
+      "searchstr = '*.png'\n",
+      "%timeit subprocess_findcopy(inpath, searchstr, outpath)\n",
+      "%timeit walk_findcopy(inpath, searchstr, outpath)\n",
+      "\n",
+      "print('\\nlarger tree')\n",
+      "inpath = '/Users/sebastian/Dropbox'\n",
+      "outpath = '/Users/sebastian/Desktop/testdir_out'\n",
+      "searchstr = '*.csv'\n",
+      "%timeit subprocess_findcopy(inpath, searchstr, outpath)\n",
+      "%timeit walk_findcopy(inpath, searchstr, outpath)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "small tree\n",
+        "100 loops, best of 3: 8.48 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n",
+        "100 loops, best of 3: 22.3 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n",
+        "\n",
+        "larger tree\n",
+        "10 loops, best of 3: 7.13 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n",
+        "1 loops, best of 3: 413 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "I have to say that I am really positvively surprised. The shell's `find` scales even better than expected!"
+     ]
     }
    ],
    "metadata": {}
diff --git a/benchmarks/timeit_tests.ipynb b/benchmarks/timeit_tests.ipynb
index 06ab26d..0e7bd18 100644
--- a/benchmarks/timeit_tests.ipynb
+++ b/benchmarks/timeit_tests.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:4f74947620f3ebd04a28a448392a201107339760170f1eb74e815a3e8b8267e8"
+  "signature": "sha256:c5925e90d7a8c3e6fb36f4e3ca876248f4ba69529367d87b73ef3da2b5415766"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -64,7 +64,8 @@
       "    - [Creating lists using conditional statements](#create_cond_list)\n",
       "- [Dictionary operations](#dict_ops) \n",
       "    - [Adding elements to a dictionary](#adding_dict_elements)\n",
-      "- [Comprehensions vs. for-loops](#comprehensions)"
+      "- [Comprehensions vs. for-loops](#comprehensions)\n",
+      "- [Copying files by searching directory trees](#find_copy)"
      ]
     },
     {
@@ -1239,13 +1240,143 @@
      ],
      "prompt_number": 28
     },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "<a name=\"find_copy\"></a>\n",
+      "<br>\n",
+      "<br>"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "# Copying files by searching directory trees"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Executing `Unix`/`Linux` shell commands:"
+     ]
+    },
     {
      "cell_type": "code",
      "collapsed": false,
-     "input": [],
+     "input": [
+      "import subprocess\n",
+      "\n",
+      "def subprocess_findcopy(path, search_str, dest):    \n",
+      "    query = 'find %s -name \"%s\" -exec cp {}\" %s \\;' %(path, search_str, dest)\n",
+      "    subprocess.call(query, shell=True)\n",
+      "    return  "
+     ],
      "language": "python",
      "metadata": {},
-     "outputs": []
+     "outputs": [],
+     "prompt_number": 2
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Using Python's `os.walk()` to search the directory tree recursively and matching patterns via `fnmatch.filter()`"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "import shutil\n",
+      "import os\n",
+      "import fnmatch\n",
+      "\n",
+      "def walk_findcopy(path, search_str, dest):\n",
+      "    for path, subdirs, files in os.walk(path):\n",
+      "        for name in fnmatch.filter(files, search_str):\n",
+      "            shutil.copy(os.path.join(path,name), dest)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [],
+     "prompt_number": 3
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "import timeit\n",
+      "\n",
+      "print('small tree')\n",
+      "inpath = '/Users/sebastian/Desktop/testdir_in'\n",
+      "outpath = '/Users/sebastian/Desktop/testdir_out'\n",
+      "searchstr = '*.png'\n",
+      "%timeit subprocess_findcopy(inpath, searchstr, outpath)\n",
+      "%timeit walk_findcopy(inpath, searchstr, outpath)\n",
+      "\n",
+      "print('\\nlarger tree')\n",
+      "inpath = '/Users/sebastian/Dropbox'\n",
+      "outpath = '/Users/sebastian/Desktop/testdir_out'\n",
+      "searchstr = '*.csv'\n",
+      "%timeit subprocess_findcopy(inpath, searchstr, outpath)\n",
+      "%timeit walk_findcopy(inpath, searchstr, outpath)"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": [
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "small tree\n",
+        "100 loops, best of 3: 8.48 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n",
+        "100 loops, best of 3: 22.3 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n",
+        "\n",
+        "larger tree\n",
+        "10 loops, best of 3: 7.13 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n",
+        "1 loops, best of 3: 413 ms per loop"
+       ]
+      },
+      {
+       "output_type": "stream",
+       "stream": "stdout",
+       "text": [
+        "\n"
+       ]
+      }
+     ],
+     "prompt_number": 4
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "I have to say that I am really positvively surprised. The shell's `find` scales even better than expected!"
+     ]
     }
    ],
    "metadata": {}