update

module4.ipynb

@@ -58,11 +58,126 @@
     "# print a goodbye message when user decides to stop the program.\n",
     "print(\"Goodbye!\")\n"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Standard streams\n",
+    "I/O Streams"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "cat streams.py\n",
+    "#!/usr/bin/env python3\n",
+    "\n",
+    "data = input(\"This will come from STDIN: \")\n",
+    "print(\"Now we write it to STDOUT: \" + data)\n",
+    "print(\"Now we generate an error to STDERR: \" + data + 1)\n",
+    "\n",
+    "./streams.py \n",
+    "This will come from STDIN: Python Rocks!\n",
+    "Now we write it to STDOUT: Python Rocks!\n",
+    "\n",
+    "cat greeting.txt \n",
+    "Well hello there, STDOUT\n",
+    "\n",
+    "cat greeting.txt \n",
+    "Well hello there, STDOUT\n",
+    "\n",
+    "ls -z"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Environment variables"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "HOME: /config\n",
+      "SHELL: \n",
+      "FRUIT: \n"
+     ]
+    }
+   ],
+   "source": [
+    "# echo $PATH\n",
+    "# /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\n",
+    "# cat variables.py\n",
+    "#!/usr/bin/env python3\n",
+    "import os\n",
+    "print(\"HOME: \" + os.environ.get(\"HOME\", \"\"))\n",
+    "print(\"SHELL: \" + os.environ.get(\"SHELL\", \"\"))\n",
+    "print(\"FRUIT: \" + os.environ.get(\"FRUIT\", \"\"))\n",
+    "# ./variables.py\n",
+    "# export FRUIT=Pineapple\n",
+    "# ./variables.py"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Command-Line Arguments and Exit Status"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "cat parameters.py \n",
+    "#!/usr/bin/env python3\n",
+    "import sys\n",
+    "print(sys.argv)\n",
+    "\n",
+    "./parameters.py\n",
+    "['./parameters.py'] \n",
+    "\n",
+    "./parameters.py one two three\n",
+    "['./parameters.py', 'one', 'two', 'three']\n",
+    "…cat example \n",
+    "New file created\n",
+    "./create_file.py example\n",
+    "Error, the file example already exists!\n",
+    "echo $?\n",
+    "1"
+   ]
   }
  ],
  "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
   "language_info": {
-   "name": "python"
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.12.3"
   }
  },
  "nbformat": 4,