{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# read"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "read -a arr\n",
    "\n",
    "for s in ${arr[@]}; do echo $s; done"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# join"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "- 1\r\n",
       "- 2\r\n",
       "+ 1\r\n",
       "+ 2\r\n",
       "+ 3\r\n",
       "+ 4\r\n",
       "- 1\r\n",
       "- 2\r\n",
       "- 3\r\n",
       "- 4\r\n",
       "- 5\r\n",
       "- 6"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "arr01=(1 2)\n",
    "printf -- '- %s\\n' \"${arr01[@]}\"\n",
    "arr02=(${arr01[@]} 3 4)\n",
    "printf -- '+ %s\\n' \"${arr02[@]}\"\n",
    "arr02+=(5 6)\n",
    "printf -- '- %s\\n' \"${arr02[@]}\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# cmd result to array"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 198,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "-rw-r--r-- 1 root root  643 May  5 17:34 /etc/hosts\n",
      "drwxr-xr-x 2 root root 4096 May 21 14:01 /etc/hosts dummyfolder\n",
      "-rw-r--r-- 1 root root  411 Oct 25  2018 /etc/hosts.allow\n",
      "-rw-r--r-- 1 root root  711 Oct 25  2018 /etc/hosts.deny\n",
      "\n"
     ]
    }
   ],
   "source": [
    "p=/etc/hosts*\n",
    "ls $p -ld\n",
    "echo\n",
    "arr1=($p)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 199,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "4\n",
      "/etc/hosts /etc/hosts dummyfolder /etc/hosts.allow /etc/hosts.deny\n",
      "\n",
      ">>>/etc/hosts<<<\n",
      ">>>/etc/hosts dummyfolder<<<\n",
      ">>>/etc/hosts.allow<<<\n",
      ">>>/etc/hosts.deny<<<\n",
      "--------------\n",
      "4\n",
      "/etc/hosts /etc/hosts dummyfolder /etc/hosts.allow /etc/hosts.deny\n",
      "\n",
      ">>>/etc/hosts<<<\n",
      ">>>/etc/hosts dummyfolder<<<\n",
      ">>>/etc/hosts.allow<<<\n",
      ">>>/etc/hosts.deny<<<\n"
     ]
    }
   ],
   "source": [
    "IFS=' '\n",
    "echo \"${#arr1[@]}\"\n",
    "echo \"${arr1[@]}\"\n",
    "echo \n",
    "for x in \"${arr1[@]}\"; do echo \">>>$x<<<\"; done\n",
    "\n",
    "echo \"--------------\"\n",
    "\n",
    "IFS=$'\\n'\n",
    "echo \"${#arr1[@]}\"\n",
    "echo \"${arr1[@]}\"\n",
    "echo \n",
    "for x in \"${arr1[@]}\"; do echo \">>>$x<<<\"; done"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 205,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "- /etc/hosts\n",
      "- /etc/hosts dummyfolder\n",
      "- /etc/hosts.allow\n",
      "- /etc/hosts.deny\n"
     ]
    }
   ],
   "source": [
    "printf -- '- %s\\n' \"${arr1[@]}\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 206,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "/etc/hosts.allow\n",
      "/etc/hosts.deny\n"
     ]
    }
   ],
   "source": [
    "arr2=($(printf -- '%s\\n' \"${arr1[@]}\" | grep [.]))\n",
    "printf -- '%s\\n' \"${arr2[@]}\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## inconsistent examples"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 187,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "4\n",
      "/etc/hosts /etc/hosts dummyfolder /etc/hosts.allow /etc/hosts.deny\n",
      "\n",
      ">>>/etc/hosts /etc/hosts dummyfolder /etc/hosts.allow /etc/hosts.deny<<<\n",
      "--------------\n",
      "4\n",
      "/etc/hosts\n",
      "/etc/hosts dummyfolder\n",
      "/etc/hosts.allow\n",
      "/etc/hosts.deny\n",
      "\n",
      ">>>/etc/hosts\n",
      "/etc/hosts dummyfolder\n",
      "/etc/hosts.allow\n",
      "/etc/hosts.deny<<<\n"
     ]
    }
   ],
   "source": [
    "IFS=' '\n",
    "echo \"${#arr1[*]}\"\n",
    "echo \"${arr1[*]}\"\n",
    "echo \n",
    "for x in \"${arr1[*]}\"; do echo \">>>$x<<<\"; done\n",
    "\n",
    "echo \"--------------\"\n",
    "\n",
    "IFS=$'\\n'\n",
    "echo \"${#arr1[*]}\"\n",
    "echo \"${arr1[*]}\"\n",
    "echo \n",
    "for x in \"${arr1[*]}\"; do echo \">>>$x<<<\"; done"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 200,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "4\n",
      "/etc/hosts /etc/hosts dummyfolder /etc/hosts.allow /etc/hosts.deny\n",
      "\n",
      ">>>/etc/hosts<<<\n",
      ">>>/etc/hosts<<<\n",
      ">>>dummyfolder<<<\n",
      ">>>/etc/hosts.allow<<<\n",
      ">>>/etc/hosts.deny<<<\n",
      "--------------\n",
      "4\n",
      "/etc/hosts /etc/hosts dummyfolder /etc/hosts.allow /etc/hosts.deny\n",
      "\n",
      ">>>/etc/hosts<<<\n",
      ">>>/etc/hosts dummyfolder<<<\n",
      ">>>/etc/hosts.allow<<<\n",
      ">>>/etc/hosts.deny<<<\n"
     ]
    }
   ],
   "source": [
    "IFS=' '\n",
    "echo ${#arr1[*]}\n",
    "echo ${arr1[*]}\n",
    "echo \n",
    "for x in ${arr1[*]}; do echo \">>>$x<<<\"; done\n",
    "\n",
    "echo \"--------------\"\n",
    "\n",
    "IFS=$'\\n'\n",
    "echo ${#arr1[*]}\n",
    "echo ${arr1[*]}\n",
    "echo \n",
    "for x in ${arr1[*]}; do echo \">>>$x<<<\"; done"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 201,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "4\n",
      "/etc/hosts /etc/hosts dummyfolder /etc/hosts.allow /etc/hosts.deny\n",
      "\n",
      ">>>/etc/hosts<<<\n",
      ">>>/etc/hosts<<<\n",
      ">>>dummyfolder<<<\n",
      ">>>/etc/hosts.allow<<<\n",
      ">>>/etc/hosts.deny<<<\n",
      "--------------\n",
      "4\n",
      "/etc/hosts /etc/hosts dummyfolder /etc/hosts.allow /etc/hosts.deny\n",
      "\n",
      ">>>/etc/hosts<<<\n",
      ">>>/etc/hosts dummyfolder<<<\n",
      ">>>/etc/hosts.allow<<<\n",
      ">>>/etc/hosts.deny<<<\n"
     ]
    }
   ],
   "source": [
    "IFS=' '\n",
    "echo ${#arr1[@]}\n",
    "echo ${arr1[@]}\n",
    "echo \n",
    "for x in ${arr1[@]}; do echo \">>>$x<<<\"; done\n",
    "\n",
    "echo \"--------------\"\n",
    "\n",
    "IFS=$'\\n'\n",
    "echo ${#arr1[@]}\n",
    "echo ${arr1[@]}\n",
    "echo \n",
    "for x in ${arr1[@]}; do echo \">>>$x<<<\"; done"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# str to array"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 169,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      ">>>x \"x2 x3\"<<<\n",
      ">>>yy<<<\n",
      ">>>zzz<<<\n",
      "count:  3\n"
     ]
    }
   ],
   "source": [
    "s='''\n",
    "x \"x2 x3\"\n",
    "yy\n",
    "zzz\n",
    "'''\n",
    "IFS=$'\\n' \n",
    "arr=($s)\n",
    "printf -- '>>>%s<<<\\n' \"${arr[@]}\"\n",
    "echo \"count: \" ${#arr[@]}  "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 143,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      ">>>x \"x2 x3\"<<<\n",
      ">>>yy<<<\n",
      ">>>zzz<<<\n",
      "count:  3\n"
     ]
    }
   ],
   "source": [
    "IFS='\n",
    "' \n",
    "arr=($s)\n",
    "printf -- '>>>%s<<<\\n' \"${arr[@]}\"\n",
    "echo \"count: \" ${#arr[*]}  "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## wrong examples"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 141,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      ">>>\n",
      "x<<<\n",
      ">>>\"x2<<<\n",
      ">>>x3\"\n",
      "yy\n",
      "zzz\n",
      "<<<\n",
      "count:  3\n"
     ]
    }
   ],
   "source": [
    "IFS=' ' \n",
    "arr=($s)\n",
    "printf -- '>>>%s<<<\\n' \"${arr[@]}\"\n",
    "echo \"count: \" ${#arr[*]}  "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 142,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      ">>>\n",
      "x \"x2 x3\"\n",
      "yy\n",
      "zzz\n",
      "<<<\n",
      "count:  1\n"
     ]
    }
   ],
   "source": [
    "IFS='\\n'\n",
    "arr=($s)\n",
    "printf -- '>>>%s<<<\\n' \"${arr[@]}\"\n",
    "echo \"count: \" ${#arr[*]}  "
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "MetaKernel Bash",
   "language": "bash",
   "name": "metakernel_bash"
  },
  "language_info": {
   "file_extension": ".sh",
   "help_links": [
    {
     "text": "MetaKernel Magics",
     "url": "https://metakernel.readthedocs.io/en/latest/source/README.html"
    }
   ],
   "mimetype": "text/x-bash",
   "name": "bash"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 4
}