BasicUnixCommands-Find-rise.ipynb

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    "# Basic *nix Commands – `find`\n"
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    "# `find`\n",
    "\n",
    "* `find` recursively examines a directory tree to look for files matching some criteria and then takes action on the selected files.\n",
    "\n",
    "* Has a difficult command line, but can be easily tamed if you break up its arguments into three components:\n"
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    "## Structure of a `find` command\n",
    "\n",
    "$$\n",
    "\\mathtt{find} \\underbrace{\\mathtt{/home}}_{\\mbox{Path list}} \\overbrace{\\mathtt{-name \\,\\, index.html}}^{\\mbox{Selection criteria}} \\underbrace{\\mathtt{\\,\\,-print}}_{\\mbox{Action}}\n",
    "$$\n"
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    "# Selection criterion\n",
    "\n",
    "|Selection criterion|Selects file|\n",
    "|-|-|\n",
    "|`-inum n`|Having inode number `n`|\n",
    "|`-type x`|If of type `x`, where `x`is `f`,`d`, or `l`|\n",
    "|`-perm nnn`|If octal permissions match `nnn`|\n",
    "|`-links n`|Having `n` links|\n",
    "|`-user usrname`| If owned by `usrname`|\n",
    "|`-group grpname`| If owned by `grpname`|\n",
    "|`-size +x[c]`| If size greater than `x` blocks (characters if `c` is also specified)|\n",
    "|`-name filename`| filename |\n",
    "|`-iname filename`| Same as above, but case-insensitive|\n",
    "|`-follow`| After following a symbolic link|\n",
    "|`-prune`| But don't descent directory if matched|\n",
    "|`-mount`| But don’t look in other file systems|\n",
    "|`-newer filename`| If modified after filename|\n"
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    "# Action\n",
    "\n",
    "|Action| Significance|\n",
    "|-|-|\n",
    "|`-print`| Prints selected file to `stdout`|\n",
    "|`-ls`| Executes `ls -lids` command on selected|\n",
    "|`-exec cmd`| Executed UNIX command `cmd` followed by `() \\;`|\n",
    "|`-ok`| Like `cmd`, except that command is executed after user confirmation|\n",
    " \n"
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    "# Operators\n",
    "\n",
    "Selection criterion can be negated or combined with or/and operators `(!, -o, -a)`\n"
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    "## Negate `(!)`, e.g.\n",
    "\n",
    "* `find . ! -name \"*.c\" -print`\n",
    "\n",
    "    * Selects all but the C program files\n"
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    "## Or `(-o)`, e.g.\n",
    "\n",
    "* `find /home \\( -name \"*.sh\" -o \"*.pl\" \\) -print`\n",
    "    * Selects files with file extension \".sh\" or \".pl\"\n"
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    "## And `(-a)`, e.g.\n",
    "\n",
    "* `find /home \\( -name \"^A\" -a \"*.pl\" \\) -print`\n",
    "    * Selects files with file extension \".pl\" that start with capital letter A\n"
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