{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# The Unix Shell: Finding Stuff\n",
    "\n",
    "Flexible ways to find files of interest."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Using `locate`\n",
    "\n",
    "Many \\*nix systems maintain a database that can be searched with locate."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "LOCATE(1)                 BSD General Commands Manual                LOCATE(1)\n",
      "\n",
      "NAME\n",
      "     locate -- find filenames quickly\n",
      "\n",
      "SYNOPSIS\n",
      "     locate [-0Scims] [-l limit] [-d database] pattern ...\n",
      "\n",
      "DESCRIPTION\n",
      "     The locate program searches a database for all pathnames which match the\n",
      "     specified pattern.  The database is recomputed periodically (usually\n",
      "     weekly or daily), and contains the pathnames of all files which are pub-\n",
      "     licly accessible.\n",
      "\n",
      "     Shell globbing and quoting characters (``*'', ``?'', ``\\'', ``['' and\n",
      "     ``]'') may be used in pattern, although they will have to be escaped from\n",
      "     the shell.  Preceding any character with a backslash (``\\'') eliminates\n",
      "     any special meaning which it may have.  The matching differs in that no\n",
      "     characters must be matched explicitly, including slashes (``/'').\n"
     ]
    }
   ],
   "source": [
    "man locate | head -n 20"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "/Users/cliburn/_teach/HTS_SummerCourse_2017/Materials/ComputationBootCampNotebooks/Wk1_Day3_PM/Unix Shell-Solutions.ipynb\n",
      "/Users/cliburn/_teach/HTS_SummerCourse_2017/Materials/ComputationBootCampNotebooks/Wk1_Day3_PM/Unix Shell.ipynb\n",
      "/Users/cliburn/_teach/data-science-foundations-2017/lessons/lesson01/.ipynb_checkpoints/01 The Unix Shell-Solutions-checkpoint.ipynb\n",
      "/Users/cliburn/_teach/data-science-foundations-2017/lessons/lesson01/.ipynb_checkpoints/01 The Unix Shell-checkpoint.ipynb\n",
      "/Users/cliburn/tmp/HTS_Summer_Course_2016/Materials/ComputationBootCampNotebooks/Wk1_Day3_PM/.ipynb_checkpoints/Unix Shell-Copy1-checkpoint.ipynb\n",
      "/Users/cliburn/tmp/HTS_Summer_Course_2016/Materials/ComputationBootCampNotebooks/Wk1_Day3_PM/.ipynb_checkpoints/Unix Shell-Solutions-checkpoint.ipynb\n",
      "/Users/cliburn/tmp/HTS_Summer_Course_2016/Materials/ComputationBootCampNotebooks/Wk1_Day3_PM/.ipynb_checkpoints/Unix Shell-checkpoint.ipynb\n",
      "/Users/cliburn/tmp/HTS_Summer_Course_2016/Materials/ComputationBootCampNotebooks/Wk1_Day3_PM/Unix Shell-Solutions.ipynb\n",
      "/Users/cliburn/tmp/HTS_Summer_Course_2016/Materials/ComputationBootCampNotebooks/Wk1_Day3_PM/Unix Shell.ipynb\n"
     ]
    }
   ],
   "source": [
    "locate -i \"unix shell\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Using `grep`\n",
    "\n",
    "`grep` is used to find regular expression patterns within files. We will cover regular expressions in a subsequent lecture, but here are the basics.\n",
    "\n",
    "```\n",
    ". represents one of any character\n",
    "+ represents one or more of the preceding pattern\n",
    "* represents zero or more of the preceding pattern\n",
    "^ matches at start of line\n",
    "$ matches at end of line\n",
    "[a|b|c] matches a or b or c\n",
    "[cat|dog] matches cat or dog\n",
    "[A-Z] matches all upper case characters\n",
    "[0-9] matches all digits\n",
    "```"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 106,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1 Hello, bash\n",
      "2 Hello, again\n",
      "3 Hello\n",
      "4 again\n"
     ]
    }
   ],
   "source": [
    "cat hello.txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Searching a file"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 108,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1 Hello, bash\n",
      "2 Hello, again\n",
      "3 Hello\n"
     ]
    }
   ],
   "source": [
    "grep \"Hello\" hello.txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Recursive searching"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 111,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./hello.txt:1 Hello, bash\n",
      "./hello.txt:2 Hello, again\n",
      "./hello.txt:3 Hello\n"
     ]
    }
   ],
   "source": [
    "grep -r \"Hello\" ./*txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Searching for words"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 112,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello.txt:1 Hello, bash\n"
     ]
    }
   ],
   "source": [
    "grep \"ash\" *.txt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 113,
   "metadata": {},
   "outputs": [
    {
     "ename": "",
     "evalue": "1",
     "output_type": "error",
     "traceback": []
    }
   ],
   "source": [
    "grep -w \"ash\" *.txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Counting words"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 114,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello.txt:3\n",
      "stderr.txt:0\n",
      "stdout.txt:0\n",
      "test1.txt:0\n"
     ]
    }
   ],
   "source": [
    "grep -c \"Hello\" *.txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### And with color!"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 115,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello.txt:1 \u001b[01;31m\u001b[KHello\u001b[m\u001b[K, bash\n",
      "hello.txt:2 \u001b[01;31m\u001b[KHello\u001b[m\u001b[K, again\n",
      "hello.txt:3 \u001b[01;31m\u001b[KHello\u001b[m\u001b[K\n"
     ]
    }
   ],
   "source": [
    "grep --color \"Hello\" *.txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Get filenames only\n",
    "\n",
    "We can use `grep` to find files matching some regular expression."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 116,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello.txt\n"
     ]
    }
   ],
   "source": [
    "grep -l \"Hello\" *.txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Using `find`\n",
    "\n",
    "While `grep` can find files matching some regular expression, the `find` command is used to locate files of interest based on various file properties. We will show a few examples."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "FIND(1)                   BSD General Commands Manual                  FIND(1)\n",
      "\n",
      "NAME\n",
      "     find -- walk a file hierarchy\n",
      "\n",
      "SYNOPSIS\n",
      "     find [-H | -L | -P] [-EXdsx] [-f path] path ... [expression]\n",
      "     find [-H | -L | -P] [-EXdsx] -f path [path ...] [expression]\n",
      "\n",
      "DESCRIPTION\n",
      "     The find utility recursively descends the directory tree for each path\n",
      "     listed, evaluating an expression (composed of the ``primaries'' and\n",
      "     ``operands'' listed below) in terms of each file in the tree.\n",
      "\n",
      "     The options are as follows:\n",
      "\n",
      "     -E      Interpret regular expressions followed by -regex and -iregex pri-\n",
      "             maries as extended (modern) regular expressions rather than basic\n",
      "             regular expressions (BRE's).  The re_format(7) manual page fully\n"
     ]
    }
   ],
   "source": [
    "man find | head -n 20"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "01_The_Unix_Shell.ipynb\n",
      "01_The_Unix_Shell_Solutions.ipynb\n",
      "The Unix Shell - File and Directory Management.ipynb\n",
      "The Unix Shell - Finding Stuff.ipynb\n",
      "The Unix Shell - Getting Help.ipynb\n",
      "The Unix Shell - Shell Scripts.ipynb\n",
      "The Unix Shell - Working with Text.ipynb\n",
      "data\n",
      "hello.txt\n",
      "one two three\n",
      "scripts\n",
      "stderr.txt\n",
      "stdout.txt\n",
      "test1.txt\n",
      "\n",
      "./data:\n",
      "iris.csv\tiris24.csv\n",
      "\n",
      "./scripts:\n",
      "avg.sh\n"
     ]
    }
   ],
   "source": [
    "ls -R"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Find by filename"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./data/iris.csv\n",
      "./data/iris24.csv\n"
     ]
    }
   ],
   "source": [
    "find . -name iris*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Find is case sensitive by default"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "find . -name \"*unix*ipynb\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Use ``-iname` for case-insensitive search"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./.ipynb_checkpoints/01_The_Unix_Shell_Solutions-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - File and Directory Management-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Finding Stuff-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Getting Help-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Shell Scripts-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Working with Text-checkpoint.ipynb\n",
      "./01_The_Unix_Shell.ipynb\n",
      "./01_The_Unix_Shell_Solutions.ipynb\n",
      "./The Unix Shell - File and Directory Management.ipynb\n",
      "./The Unix Shell - Finding Stuff.ipynb\n",
      "./The Unix Shell - Getting Help.ipynb\n",
      "./The Unix Shell - Shell Scripts.ipynb\n",
      "./The Unix Shell - Working with Text.ipynb\n"
     ]
    }
   ],
   "source": [
    "find . -iname \"*unix*ipynb\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Exclude unwanted directories from search"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./01_The_Unix_Shell.ipynb\n",
      "./01_The_Unix_Shell_Solutions.ipynb\n",
      "./The Unix Shell - File and Directory Management.ipynb\n",
      "./The Unix Shell - Finding Stuff.ipynb\n",
      "./The Unix Shell - Getting Help.ipynb\n",
      "./The Unix Shell - Shell Scripts.ipynb\n",
      "./The Unix Shell - Working with Text.ipynb\n"
     ]
    }
   ],
   "source": [
    "find . -not -path \"*ipynb_checkpoints/*\" -iname \"*unix*ipynb\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Limiting recursion depth"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 103,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./.ipynb_checkpoints\n",
      "./data/iris.csv\n",
      "./data/iris24.csv\n",
      "./hello.txt\n",
      "./scripts\n",
      "./stderr.txt\n",
      "./stdout.txt\n",
      "./test1.txt\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*[csv|txt]\" "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 104,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./.ipynb_checkpoints\n",
      "./hello.txt\n",
      "./scripts\n",
      "./stderr.txt\n",
      "./stdout.txt\n",
      "./test1.txt\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*[csv|txt]\" -maxdepth 1"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Find by time"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Files notebooks created more than 1 day ago"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./01_The_Unix_Shell.ipynb\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*ipynb\" -ctime +1"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Files  notebooks modified within the last day"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./.ipynb_checkpoints/01_The_Unix_Shell_Solutions-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - File and Directory Management-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Finding Stuff-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Getting Help-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Shell Scripts-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Working with Text-checkpoint.ipynb\n",
      "./01_The_Unix_Shell_Solutions.ipynb\n",
      "./The Unix Shell - File and Directory Management.ipynb\n",
      "./The Unix Shell - Finding Stuff.ipynb\n",
      "./The Unix Shell - Getting Help.ipynb\n",
      "./The Unix Shell - Shell Scripts.ipynb\n",
      "./The Unix Shell - Working with Text.ipynb\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*ipynb\" -mtime -1"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Files modified in the past 15 minutes"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./The Unix Shell - Finding Stuff.ipynb\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*ipynb\" -mmin -15"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Delete text file modified in the last minute or less"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "touch Delete_Me.txt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 58,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Delete_Me.txt\thello.txt\tstdout.txt\n",
      "Delete_Me2.txt\tstderr.txt\ttest1.txt\n"
     ]
    }
   ],
   "source": [
    "ls *txt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 59,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./Delete_Me.txt\n",
      "./Delete_Me2.txt\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*txt\" -mmin -1 "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 60,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "find . -name \"*txt\" -mmin -1 -delete"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 61,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello.txt\tstderr.txt\tstdout.txt\ttest1.txt\n"
     ]
    }
   ],
   "source": [
    "ls *txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Alternative more common way is to pipe to rm\n",
    "\n",
    "We use `xargs` to split the output into sublists that can be processed one at a time by `rm` "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 73,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "touch Delete_Me2.txt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 74,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Delete_Me2.txt\thello.txt\tstderr.txt\tstdout.txt\ttest1.txt\n"
     ]
    }
   ],
   "source": [
    "ls *txt"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 76,
   "metadata": {},
   "outputs": [],
   "source": [
    "find . -name \"*txt\" -mmin -1 | xargs rm"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 77,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello.txt\tstderr.txt\tstdout.txt\ttest1.txt\n"
     ]
    }
   ],
   "source": [
    "ls *txt"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Find files containing a phrase\n",
    "\n",
    "`find` can be combined with `grep` to first find a subset of files of interest, and then looking for lines containing a regular expression within those files."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 67,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./.ipynb_checkpoints/01_The_Unix_Shell_Solutions-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - File and Directory Management-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Finding Stuff-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Getting Help-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Shell Scripts-checkpoint.ipynb\n",
      "./.ipynb_checkpoints/The Unix Shell - Working with Text-checkpoint.ipynb\n",
      "./01_The_Unix_Shell.ipynb\n",
      "./01_The_Unix_Shell_Solutions.ipynb\n",
      "./The Unix Shell - File and Directory Management.ipynb\n",
      "./The Unix Shell - Finding Stuff.ipynb\n",
      "./The Unix Shell - Getting Help.ipynb\n",
      "./The Unix Shell - Shell Scripts.ipynb\n",
      "./The Unix Shell - Working with Text.ipynb\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*ipynb\" "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 89,
   "metadata": {
    "scrolled": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./hello.txt:2 Hello, again\n",
      "./hello.txt:4 again\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*txt\" | xargs grep \"again\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### If filenames can contain spaces, we need to do more work\n",
    "\n",
    "By default, `args` uses spaces as delimiters, and we will error messages since fragments of filenames will be passed to `grep`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 98,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "grep: ./The: No such file or directory\n",
      "grep: Unix: No such file or directory\n",
      "grep: Shell: No such file or directory\n",
      "grep: File: No such file or directory\n",
      "grep: and: No such file or directory\n",
      "grep: Directory: No such file or directory\n",
      "grep: Management.ipynb: No such file or directory\n",
      "grep: ./The: No such file or directory\n",
      "grep: Unix: No such file or directory\n",
      "grep: Shell: No such file or directory\n",
      "grep: (standard input): Bad file descriptor\n",
      "grep: Finding: No such file or directory\n",
      "grep: Stuff.ipynb: No such file or directory\n",
      "grep: ./The: No such file or directory\n",
      "grep: Unix: No such file or directory\n",
      "grep: Shell: No such file or directory\n",
      "grep: (standard input): Bad file descriptor\n",
      "grep: Getting: No such file or directory\n",
      "grep: Help.ipynb: No such file or directory\n",
      "grep: ./The: No such file or directory\n",
      "grep: Unix: No such file or directory\n",
      "grep: Shell: No such file or directory\n",
      "grep: (standard input): Bad file descriptor\n",
      "grep: Shell: No such file or directory\n",
      "grep: Scripts.ipynb: No such file or directory\n",
      "grep: ./The: No such file or directory\n",
      "grep: Unix: No such file or directory\n",
      "grep: Shell: No such file or directory\n",
      "grep: (standard input): Bad file descriptor\n",
      "grep: Working: No such file or directory\n",
      "grep: with: No such file or directory\n",
      "grep: Text.ipynb: No such file or directory\n"
     ]
    },
    {
     "ename": "",
     "evalue": "1",
     "output_type": "error",
     "traceback": []
    }
   ],
   "source": [
    "find . -name \"*Unix*\" -not -path \"*.ipynb_checkpoints/*\" | xargs grep -i \"Cipher\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "To get around, use the `-print0` argumnent to `find` paired with the `-0` argument to `xargs` to change the delimiter to the NUL character."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 97,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "./The Unix Shell - Getting Help.ipynb:      \"blowfish(n)              - Implementation of the Blowfish block cipher\\n\"\n",
      "./The Unix Shell - Getting Help.ipynb:      \"blowfish(n)              - Implementation of the Blowfish block cipher\\n\"\n",
      "./The Unix Shell - Getting Help.ipynb:      \"blowfish(n)                  Blowfish Block Cipher                 blowfish(n)\\n\",\n",
      "./The Unix Shell - Getting Help.ipynb:      \"       blowfish - Implementation of the Blowfish block cipher\\n\",\n"
     ]
    }
   ],
   "source": [
    "find . -name \"*Unix*\" -not -path \"*.ipynb_checkpoints/*\" -print0 | xargs -0 grep -i \"Cipher\""
   ]
  }
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