BasicUnixCommands-Pipes_and_Redirects-rise.ipynb

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   "source": [
    "# Basic *nix Commands – Pipes & Redirects\n"
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    "# Redirection\n"
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    "## Redirect command output to a file\n",
    "* Think of redirection characters as arrows. \n",
    "* e.g., `ls /dev > test.txt`\n",
    "    * redirects the output of ls into a new file named test.txt\n"
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    "## Append command **output** to the end of a file\n",
    "* e.g., `ls /proc >> test.txt`\n"
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    "## Redirect input from other than stdin\n",
    "* Works for commands that normally use keyboard input.\n",
    "* e.g., `echo ‘print ‘‘Hello, World!’’ ’ > hello.py && python < hello.py`\n",
    "    * The && means continue with next command \n"
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    "# std*\n",
    "\n",
    "There are 3 standard I/O file stream descriptors\n"
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    "## stdin\n",
    "* 0\n",
    "    * Use `<`\n",
    "\n",
    "                      \n"
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    "## stdout\n",
    "* 1\n",
    "    * `>` is the same as `1>`\n"
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    "## stderr\n",
    "* 2\n",
    "* Most often used to redirect to nowhere\n",
    "    * e.g., `find / -name ls 2>/dev/null`\n"
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   "source": [
    "# Pipes\n"
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    "## `|`\n",
    "  \n",
    "* As the name implies, a pipe (`|`) takes the output of one command to the input of another command\n",
    "    * e.g., `ls /usr/sbin | less`\n",
    "    \n",
    "* We can actually write short \"programs\" by stringing pipes\n",
    "together.\n"
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    "## `tee`\n",
    "\n",
    "* Splits a data stream so it flows both into a specified file and continues as `tee`'s `stdout`\n",
    "\n",
    "* Useful for saving intermediate steps in a long string of pipes.\n",
    "    * e.g., `ls /usr/sbin | tee processes.txt | less`\n"
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