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                        #!
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                        Interactive vs Non-Interactive Shell
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                        Login vs Non-Login Shell
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                        etc
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                        Test
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                            <b>3.1.</b>
                        
                        Operators
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                            <b>4.</b>
                        
                        Subshells
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                        Process Creation
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                        Commands
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                            <b>5.1.</b>
                        
                        Builtin Commands
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                        read
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                        printf
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                        eval
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                        getopts
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                        Keyword Commands
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                        Compound Commands
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                        Special Commands
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                        expr
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                        grep
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                        find
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                        Arrays
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                            <b>7.</b>
                        
                        Shell Metacharacters
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                            <b>7.1.</b>
                        
                        Precedence
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                            <b>8.</b>
                        
                        Expansions and Substitutions
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                            <b>8.1.</b>
                        
                        Brace Expansion
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                            <b>8.2.</b>
                        
                        Tilde Expansion
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                            <b>8.3.</b>
                        
                        Parameter Expansion
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                            <b>8.4.</b>
                        
                        Arithmetic Expansion
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                            <b>8.5.</b>
                        
                        Command Substitution
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                            <b>8.6.</b>
                        
                        Process Substitution
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                            <b>8.7.</b>
                        
                        Word Splitting
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                            <b>8.8.</b>
                        
                        Filename Expansion
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                        Job Control
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                            <b>9.1.</b>
                        
                        Session and Process Group
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                            <b>9.2.</b>
                        
                        Process State Codes
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                            <b>9.3.</b>
                        
                        TTY
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                            <b>9.4.</b>
                        
                        Mutual Exclusion
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                            <b>10.</b>
                        
                        Redirections
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                            <b>10.1.</b>
                        
                        File Descriptors
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                            <b>10.2.</b>
                        
                        &lt;&lt; , &lt;&lt;&lt;
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                            <b>10.3.</b>
                        
                        Pipe
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                            <b>10.4.</b>
                        
                        Named Pipe
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                            <b>10.5.</b>
                        
                        Buffering
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                            <b>11.</b>
                        
                        Signals and Traps
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                            <b>11.1.</b>
                        
                        kill
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                            <b>11.2.</b>
                        
                        trap
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                            <b>11.3.</b>
                        
                        Signals Table
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                            <b>12.</b>
                        
                        Command Aliases
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                            <b>13.</b>
                        
                        Command History
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                            <b>14.</b>
                        
                        Command Completion
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                            <b>15.</b>
                        
                        Readline
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                            <b>16.</b>
                        
                        Colors and Prompt
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                            <b>17.</b>
                        
                        Locale
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                            <b>18.</b>
                        
                        sh
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                            <b>19.</b>
                        
                        Debugging
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                            <b>20.</b>
                        
                        Shell Variables
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                            <b>20.1.</b>
                        
                        Positional Parameters
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                            <b>20.2.</b>
                        
                        Special Parameters
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                            <b>21.</b>
                        
                        Shell Options
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                            <b>21.1.</b>
                        
                        Command-line options
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                            <b>22.</b>
                        
                        Tips
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        <li class="chapter " data-level="23" data-path="closing.html">
            
                
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                            <b>23.</b>
                        
                        맺음말
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                            <b>24.</b>
                        
                        별책부록
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    <h1>
        <i class="fa fa-circle-o-notch fa-spin"></i>
        <a href="./" >Introduction</a>
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                    <section class="normal" id="section-">
                    
                        <h1 id="-">&lt;&lt; , &lt;&lt;&lt;</h1>
<p><code>&lt;&lt;</code> ( here document ), <code>&lt;&lt;&lt;</code> ( here string ) &#xC740; &#xC2E4;&#xD589; &#xC911;&#xC5D0; &#xC784;&#xC2DC; &#xD30C;&#xC77C;&#xC744; &#xB9CC;&#xB4E4;&#xC5B4;&#xC11C; stdin &#xC5D0; &#xC5F0;&#xACB0;&#xD569;&#xB2C8;&#xB2E4;.  &#xADF8;&#xB7EC;&#xBBC0;&#xB85C; <code>echo</code> &#xBA85;&#xB839; &#xB300;&#xC2E0;&#xC5D0; <code>cat</code> &#xBA85;&#xB839;&#xC744; &#xC0AC;&#xC6A9;&#xD569;&#xB2C8;&#xB2E4;. &#xC544;&#xB798;&#xB294; <code>ls -l</code> &#xBA85;&#xB839;&#xC758; &#xC778;&#xC218;&#xB85C; here docuemnt &#xB97C; &#xC0AC;&#xC6A9;&#xD558;&#xC600;&#xB294;&#xB370; stdin &#xC785;&#xB825;&#xC73C;&#xB85C; sh-thd.Th1cFU &#xC784;&#xC2DC; &#xD30C;&#xC77C;&#xC774; &#xC0AC;&#xC6A9;&#xB41C; &#xD6C4; &#xC0AD;&#xC81C;&#xB41C; &#xAC83;&#xC744; &#xBCFC;&#xC218;&#xAC00; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<blockquote>
<p><code>sh</code> &#xC5D0;&#xC11C;&#xB294; <code>&lt;&lt;</code> &#xB9CC; &#xC0AC;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
</blockquote>
<p><img src="images/here_document.png" alt=""></p>
<pre><code class="lang-bash">$ <span class="hljs-built_in">stat</span> -L -c <span class="hljs-string">&quot;%F&quot;</span> /dev/stdin &lt;&lt;EOF
<span class="hljs-number">123</span>
EOF
regular file

$ <span class="hljs-built_in">stat</span> -L -c <span class="hljs-string">&quot;%F&quot;</span> /dev/stdin &lt;&lt;&lt; <span class="hljs-number">123</span>
regular file
</code></pre>
<p><code>&lt;&lt;</code>, <code>&lt;&lt;&lt;</code> &#xC67C;&#xCABD;&#xC5D0; &#xACF5;&#xBC31;&#xC5C6;&#xC774; &#xBD99;&#xC5EC;&#xC11C; file descriptor &#xB97C; &#xC0AC;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<p><img src="images/here_document2.png" alt=""></p>
<pre><code class="lang-bash">$ <span class="hljs-number">3</span>&lt;&lt;&lt; hello &lt;&amp;<span class="hljs-number">3</span> cat       <span class="hljs-comment"># &lt;&amp;3 &#xB294; 0&lt;&amp;3 &#xC640; &#xAC19;&#xC740; &#xAC83;&#xC784;</span>
hello

$ <span class="hljs-number">3</span>&lt;&lt;END cat /dev/fd/<span class="hljs-number">3</span>
&gt; hello
&gt; END
hello
---------------------------------------------------

$ <span class="hljs-built_in">exec</span> <span class="hljs-number">3</span>&lt;&lt;END
&gt; <span class="hljs-number">111</span>
&gt; <span class="hljs-number">222</span>
&gt; END

$ ls <span class="hljs-operator">-l</span> /proc/$$/fd/
total <span class="hljs-number">0</span>
lrwx------ <span class="hljs-number">1</span> mug896 mug896 <span class="hljs-number">64</span> <span class="hljs-number">2018</span>-<span class="hljs-number">01</span>-<span class="hljs-number">05</span> <span class="hljs-number">18</span>:<span class="hljs-number">51</span> <span class="hljs-number">0</span> -&gt; /dev/pts/<span class="hljs-number">15</span>
lrwx------ <span class="hljs-number">1</span> mug896 mug896 <span class="hljs-number">64</span> <span class="hljs-number">2018</span>-<span class="hljs-number">01</span>-<span class="hljs-number">05</span> <span class="hljs-number">18</span>:<span class="hljs-number">51</span> <span class="hljs-number">1</span> -&gt; /dev/pts/<span class="hljs-number">15</span>
lrwx------ <span class="hljs-number">1</span> mug896 mug896 <span class="hljs-number">64</span> <span class="hljs-number">2018</span>-<span class="hljs-number">01</span>-<span class="hljs-number">05</span> <span class="hljs-number">18</span>:<span class="hljs-number">51</span> <span class="hljs-number">2</span> -&gt; /dev/pts/<span class="hljs-number">15</span>
lrwx------ <span class="hljs-number">1</span> mug896 mug896 <span class="hljs-number">64</span> <span class="hljs-number">2018</span>-<span class="hljs-number">01</span>-<span class="hljs-number">05</span> <span class="hljs-number">18</span>:<span class="hljs-number">51</span> <span class="hljs-number">255</span> -&gt; /dev/pts/<span class="hljs-number">15</span>
lr-x------ <span class="hljs-number">1</span> mug896 mug896 <span class="hljs-number">64</span> <span class="hljs-number">2018</span>-<span class="hljs-number">01</span>-<span class="hljs-number">05</span> <span class="hljs-number">18</span>:<span class="hljs-number">51</span> <span class="hljs-number">3</span> -&gt; /tmp/sh-thd.<span class="hljs-number">0</span>bYLMF (deleted)

$ cat /dev/fd/<span class="hljs-number">3</span>
<span class="hljs-number">111</span>
<span class="hljs-number">222</span>
$ cat /dev/fd/<span class="hljs-number">3</span>
<span class="hljs-number">111</span>
<span class="hljs-number">222</span>

$ cat &lt;&amp;<span class="hljs-number">3</span>
<span class="hljs-number">111</span>
<span class="hljs-number">222</span>
$ cat &lt;&amp;<span class="hljs-number">3</span>
$            <span class="hljs-comment"># &lt;&amp;3 &#xB294; &#xD30C;&#xC77C; &#xD3EC;&#xC9C0;&#xC158;&#xC774; &#xC774;&#xB3D9;&#xD558;&#xBBC0;&#xB85C;</span>

$ <span class="hljs-built_in">exec</span> <span class="hljs-number">3</span>&gt;&amp;-
-----------------------------------------

<span class="hljs-comment"># &#xD30C;&#xC774;&#xD504;&#xB85C; &#xC778;&#xD574; stdin &#xC774; &#xC0AC;&#xC6A9; &#xC911; &#xC77C; &#xACBD;&#xC6B0;</span>
$ <span class="hljs-built_in">command</span> ... | sed <span class="hljs-operator">-f</span> /dev/fd/<span class="hljs-number">3</span> <span class="hljs-number">3</span>&lt;&lt;EOF
...
EOF

$ <span class="hljs-built_in">command</span> ... | awk <span class="hljs-operator">-f</span> /dev/fd/<span class="hljs-number">3</span> <span class="hljs-number">3</span>&lt;&lt;\EOF
...
EOF
</code></pre>
<h2 id="here-document">&lt;&lt; here document</h2>
<p>sed, awk &#xAC19;&#xC740; &#xBA85;&#xB839;&#xC744; &#xC791;&#xC131;&#xD560; &#xB54C;&#xB294; quotes &#xC744; &#xC0AC;&#xC6A9;&#xD558;&#xBBC0;&#xB85C;
&#xB3D9;&#xC77C;&#xD55C; quotes &#xC744; &#xCD9C;&#xB825;&#xC5D0; &#xC0AC;&#xC6A9;&#xD558;&#xB824;&#xBA74; escape &#xACFC;&#xC815;&#xC744; &#xAC70;&#xCCD0;&#xC57C; &#xD558;&#xB294;&#xB370;&#xC694;.
here document &#xB97C; &#xC774;&#xC6A9;&#xD558;&#xBA74; &#xD30C;&#xC77C;&#xC5D0;&#xC11C; &#xC791;&#xC131;&#xD558;&#xB294; &#xAC83;&#xACFC; &#xAC19;&#xC774; quotes &#xC744; escape &#xD560; &#xD544;&#xC694;&#xAC00; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xB610;&#xD55C; &#xBCF8;&#xBB38; &#xB0B4;&#xC6A9; &#xC911;&#xC5D0; &#xBCC0;&#xC218;&#xB97C; &#xC0AC;&#xC6A9;&#xD560; &#xC218;&#xB3C4; &#xC788;&#xC5B4;&#xC11C; &#xC5EC;&#xB7EC;&#xBAA8;&#xB85C; &#xD3B8;&#xB9AC;&#xD55C; &#xAE30;&#xB2A5;&#xC785;&#xB2C8;&#xB2E4;.</p>
<p>here document &#xB294; &#xBCF8;&#xBB38;&#xC758; &#xCC98;&#xC74C;&#xACFC; &#xB05D;&#xC744; &#xBCC4;&#xB3C4;&#xC758; &#xB808;&#xC774;&#xBE14;&#xB85C; &#xAD6C;&#xBD84;&#xD558;&#xB294;&#xB370; &#xC774;&#xB54C; &#xC0AC;&#xC6A9;&#xB418;&#xB294;
&#xAD6C;&#xBD84;&#xC790; &#xBA85;&#xC740; &#xC784;&#xC758;&#xB85C; &#xB9CC;&#xB4E4;&#xC5B4; &#xC0AC;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xD55C;&#xAC00;&#xC9C0; &#xC8FC;&#xC758;&#xD560; &#xC810;&#xC740; &#xB9C8;&#xC9C0;&#xB9C9; &#xC904;&#xC740; &#xAD6C;&#xBD84;&#xC790; &#xC678;&#xC5D0; &#xB2E4;&#xB978; &#xBB38;&#xC790;&#xAC00; &#xC640;&#xC11C;&#xB294; &#xC548;&#xB429;&#xB2C8;&#xB2E4; ( &#xACF5;&#xBC31;&#xB3C4; &#xC548;&#xB428; ).
&#xAD6C;&#xBD84;&#xC790;&#xB97C; quote &#xD558;&#xAC70;&#xB098; escape &#xD558;&#xBA74; &#xBCC0;&#xC218;&#xD655;&#xC7A5;, &#xBA85;&#xB839;&#xCE58;&#xD658;&#xC774; &#xC77C;&#xC5B4;&#xB098;&#xC9C0; &#xC54A;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash"><span class="hljs-comment"># quotes &#xC744; escape &#xD558;&#xC9C0; &#xC54A;&#xACE0; &#xC0AC;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC5B4;&#xC11C; echo &#xBA85;&#xB839; &#xB300;&#xC2E0;&#xC5D0; &#xCD9C;&#xB825;&#xC5D0; &#xC0AC;&#xC6A9;&#xD558;&#xAE30; &#xC88B;&#xC2B5;&#xB2C8;&#xB2E4;.</span>
<span class="hljs-comment"># &#xC608;) &#xBA85;&#xB839;&#xC758; help &#xBA54;&#xC2DC;&#xC9C0; &#xC791;&#xC131;</span>
$ cat &lt;&lt;EOF
&gt; this is <span class="hljs-string">&quot;double quotes&quot;</span>
&gt; this is <span class="hljs-string">&apos;single quotes&apos;</span>
&gt; EOF

this is <span class="hljs-string">&quot;double quotes&quot;</span>
this is <span class="hljs-string">&apos;single quotes&apos;</span>

<span class="hljs-comment"># &#xAE30;&#xBCF8;&#xC801;&#xC73C;&#xB85C; &#xBCF8;&#xBB38;&#xC5D0;&#xC11C; &#xBCC0;&#xC218;&#xD655;&#xC7A5;, &#xBA85;&#xB839;&#xCE58;&#xD658;&#xC774; &#xC77C;&#xC5B4;&#xB09C;&#xB2E4;.</span>
$ AA=<span class="hljs-number">100</span>
$ cat &lt;&lt;ABC     <span class="hljs-comment"># &#xAD6C;&#xBD84;&#xC790; ABC</span>
&gt; here <span class="hljs-variable">$AA</span>
&gt; document $(date +%D)
&gt; ABC

here <span class="hljs-number">100</span>
document <span class="hljs-number">07</span>/<span class="hljs-number">23</span>/<span class="hljs-number">15</span>

<span class="hljs-comment"># &#xAD6C;&#xBD84;&#xC790;&#xB97C; quote &#xD558;&#xAC70;&#xB098; escape &#xD558;&#xBA74; &#xBCC0;&#xC218;&#xD655;&#xC7A5;, &#xBA85;&#xB839;&#xCE58;&#xD658;&#xC774; &#xC548;&#xB41C;&#xB2E4;.</span>
$ AA=<span class="hljs-number">100</span>
$ cat &lt;&lt;<span class="hljs-string">&apos;END&apos;</span>   <span class="hljs-comment"># &#xB610;&#xB294; &lt;&lt;\END</span>
&gt; here <span class="hljs-variable">$AA</span>
&gt; document $(date +%D)
&gt; END

here <span class="hljs-variable">$AA</span>
document $(date +%D)

<span class="hljs-comment"># &#xB9C8;&#xC9C0;&#xB9C9; &#xC904;&#xC740; &#xAD6C;&#xBD84;&#xC790; &#xC678;&#xC5D0; &#xB2E4;&#xB978; &#xBB38;&#xC790;&#xAC00; &#xC624;&#xBA74; &#xC548;&#xB429;&#xB2C8;&#xB2E4;.</span>
$ cat &lt;&lt;@       <span class="hljs-comment"># &#xAD6C;&#xBD84;&#xC790; @</span>
&gt; @@@
&gt; @@
&gt; @
@@@
@@
</code></pre>
<p>awk, sed &#xBA85;&#xB839; &#xC0AC;&#xC6A9;&#xC608;</p>
<pre><code class="lang-bash"><span class="hljs-comment"># here document &#xB294; stdin &#xC5D0; &#xC5F0;&#xACB0;&#xB418;&#xBBC0;&#xB85C; &apos;-f -&apos;  &#xC635;&#xC158;&#xC744; &#xC0AC;&#xC6A9; (&apos;-&apos; &#xB294; stdin &#xC744; &#xB098;&#xD0C0;&#xB0C4;)</span>
$ awk <span class="hljs-operator">-f</span> - &lt;&lt;\EOF
&gt; BEGIN { <span class="hljs-built_in">print</span> <span class="hljs-string">&quot;&apos;&apos;print single quotes easily&apos;&apos;&quot;</span> }
&gt; EOF
<span class="hljs-string">&apos;&apos;</span><span class="hljs-built_in">print</span> single quotes easily<span class="hljs-string">&apos;&apos;</span>

<span class="hljs-comment"># single, double quotes &#xC744; &#xC27D;&#xAC8C; &#xCD9C;&#xB825;&#xD560; &#xC218; &#xC788;&#xB2E4;.</span>
<span class="hljs-comment"># ( &#xD30C;&#xC774;&#xD504; &#xB85C;&#xC778;&#xD574; stdin &#xC774; &#xC0AC;&#xC6A9; &#xC911;&#xC774;&#xBBC0;&#xB85C; -f /dev/fd/3 &#xB97C; &#xC0AC;&#xC6A9; )</span>
$ <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;print quotes easily&quot;</span> | sed <span class="hljs-operator">-f</span> /dev/fd/<span class="hljs-number">3</span> <span class="hljs-number">3</span>&lt;&lt;EOF
&gt; s/.*/<span class="hljs-string">&apos;&apos;</span>&amp;<span class="hljs-string">&quot;&quot;</span>/
&gt; EOF
<span class="hljs-string">&apos;&apos;</span><span class="hljs-built_in">print</span> quotes easily<span class="hljs-string">&quot;&quot;</span>

$ <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;print quotes easily&quot;</span> | sed <span class="hljs-string">&quot;<span class="hljs-variable">$( cat &lt;&lt;EOF
&gt; s/.*/&apos;&apos;&amp;&quot;&quot;/                                     
&gt; EOF
&gt; )</span>&quot;</span>
<span class="hljs-string">&apos;&apos;</span><span class="hljs-built_in">print</span> quotes easily<span class="hljs-string">&quot;&quot;</span>
</code></pre>
<h4 id="heredoc-&#xC744;-&#xC774;&#xC6A9;&#xD574;-shell-script-&#xC2E4;&#xD589;&#xD558;&#xAE30;">Heredoc &#xC744; &#xC774;&#xC6A9;&#xD574; shell script &#xC2E4;&#xD589;&#xD558;&#xAE30;</h4>
<p>Heredoc &#xC73C;&#xB85C; shell script &#xB97C; &#xC791;&#xC131;&#xD574; &#xC2E4;&#xD589;&#xD560; &#xB54C; &#xC778;&#xC218; &#xC804;&#xB2EC;&#xC774; &#xD544;&#xC694;&#xD560; &#xACBD;&#xC6B0; <code>-s</code> &#xC635;&#xC158;&#xC744; &#xC0AC;&#xC6A9;&#xD574;&#xC57C; &#xD569;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash">$ bash &lt;&lt;\EOF <span class="hljs-operator">-s</span> foo bar zoo                 $ bash &lt;&lt;\EOF foo bar zoo
<span class="hljs-built_in">echo</span> <span class="hljs-variable">$1</span>, <span class="hljs-variable">$2</span>, <span class="hljs-variable">$3</span>                              <span class="hljs-built_in">echo</span> <span class="hljs-variable">$1</span>, <span class="hljs-variable">$2</span>, <span class="hljs-variable">$3</span>
<span class="hljs-built_in">echo</span> <span class="hljs-variable">$#</span>                                      <span class="hljs-built_in">echo</span> <span class="hljs-variable">$#</span>
EOF                                          EOF
                                             bash: foo: No such file or directory
foo, bar, zoo 
<span class="hljs-number">3</span>
-----------------------------

$ <span class="hljs-built_in">alias</span> bashx=<span class="hljs-string">&apos;bash &lt;&lt;\@ -s&apos;</span>

$ bashx <span class="hljs-number">11</span> <span class="hljs-number">22</span> <span class="hljs-number">33</span>
&gt; <span class="hljs-built_in">echo</span> <span class="hljs-variable">$0</span>, <span class="hljs-variable">$1</span>, <span class="hljs-variable">$2</span>, <span class="hljs-variable">$3</span>
&gt; <span class="hljs-built_in">echo</span> <span class="hljs-variable">$#</span>
&gt; @

bash, <span class="hljs-number">11</span>, <span class="hljs-number">22</span>, <span class="hljs-number">33</span>
<span class="hljs-number">3</span>
</code></pre>
<h4 id="&#xC18C;&#xC2A4;&#xCF54;&#xB4DC;-&#xD30C;&#xC77C;-&#xC5C6;&#xC774;-heredoc-&#xC744;-&#xC774;&#xC6A9;&#xD574;-&#xCEF4;&#xD30C;&#xC77C;-&#xD558;&#xAE30;">&#xC18C;&#xC2A4;&#xCF54;&#xB4DC; &#xD30C;&#xC77C; &#xC5C6;&#xC774; heredoc &#xC744; &#xC774;&#xC6A9;&#xD574; &#xCEF4;&#xD30C;&#xC77C; &#xD558;&#xAE30;</h4>
<pre><code class="lang-bash"><span class="hljs-comment"># &#xBA85;&#xB839;&#xD589; &#xC0C1;&#xC5D0;&#xC11C; &#xCCAB;&#xBC88;&#xC9F8; &apos;-&apos; &#xB294; stdout &#xC744;( -o &#xC635;&#xC158;&#xACFC; ), &#xB450;&#xBC88;&#xC9F8; &apos;-&apos; &#xB294; stdin &#xC744; &#xB098;&#xD0C0;&#xB0C4;</span>
<span class="hljs-comment"># gcc &#xB294; &#xD30C;&#xC77C; &#xD655;&#xC7A5;&#xC790;&#xB97C; &#xD1B5;&#xD574; c, c++ &#xD30C;&#xC77C;&#xC744; &#xAD6C;&#xBD84;&#xD558;&#xB294;&#xB370; &#xC9C0;&#xAE08;&#xC740; stdin &#xC73C;&#xB85C;&#xBD80;&#xD130;</span>
<span class="hljs-comment"># &#xC785;&#xB825;&#xC744; &#xBC1B;&#xC73C;&#xBBC0;&#xB85C; -x &#xC635;&#xC158;&#xC744; &#xC774;&#xC6A9;&#xD574; c &#xD30C;&#xC77C;&#xC784;&#xC744; &#xBA85;&#xC2DC;&#xD574;&#xC57C; &#xD569;&#xB2C8;&#xB2E4;. ( c++ &#xC758; &#xACBD;&#xC6B0;&#xB294; -xc++ )</span>
$ gcc -S -xc -o - - &lt;&lt;\EOF
int a = <span class="hljs-number">123</span>;
int <span class="hljs-function"><span class="hljs-title">foo</span></span>() { 
    int b = <span class="hljs-number">234</span>;
    int c = a + b;
    <span class="hljs-built_in">return</span> c;
}                     
EOF
        .file   <span class="hljs-string">&quot;&quot;</span>
        .intel_syntax noprefix
        .text
        .globl  a
        . . . .
        . . . .
</code></pre>
<h4 id="here-document-&#xB97C;-&#xD30C;&#xC77C;&#xB85C;-&#xC4F0;&#xAE30;">Here document &#xB97C; &#xD30C;&#xC77C;&#xB85C; &#xC4F0;&#xAE30;</h4>
<pre><code class="lang-bash">$ cat &lt;&lt;\END &gt; file.conf     <span class="hljs-comment"># &lt;&lt;END &#xB294; 0&lt;&lt;END &#xACFC; &#xAC19;&#xC740; &#xAC83;&#xC784;</span>
here     = <span class="hljs-number">100</span>
document = <span class="hljs-number">200</span>
END

$ &lt;&lt;\END cat &gt; file.conf
here     = <span class="hljs-number">100</span>
document = <span class="hljs-number">200</span>
END

$ cat &gt; file.conf &lt;&lt;\END
here     = <span class="hljs-number">100</span>
document = <span class="hljs-number">200</span>
END
</code></pre>
<h4 id="here-document-&#xB97C;-&#xD30C;&#xC774;&#xD504;&#xB85C;-&#xC804;&#xB2EC;&#xD558;&#xAE30;">Here document &#xB97C; &#xD30C;&#xC774;&#xD504;&#xB85C; &#xC804;&#xB2EC;&#xD558;&#xAE30;</h4>
<pre><code class="lang-bash">$ sqlite3 mydatabase &lt;&lt;\@ | awk -F <span class="hljs-string">&apos;\t&apos;</span> \
<span class="hljs-string">&apos;
BEGIN { print &quot;&lt;table&gt;&quot; }
{ printf &quot;&lt;tr&gt;&lt;td&gt;%s&lt;/td&gt;&lt;td&gt;%s&lt;/td&gt;&lt;/tr&gt;\n&quot;, $1, $2 }
END { print &quot;&lt;/table&gt;&quot; }
&apos;</span>
.mode list
.separator \t
.header off
SELECT name,phone FROM person;
@

<span class="hljs-comment"># &#xB610;&#xB294;</span>
$ sqlite3 mydatabase &lt;&lt;\@ | awk <span class="hljs-operator">-f</span> /dev/fd/<span class="hljs-number">3</span> <span class="hljs-number">3</span>&lt;&lt;\@@ -F <span class="hljs-string">&apos;\t&apos;</span>
.mode list
.separator \t
.header off
SELECT name,phone FROM person;
@
BEGIN { <span class="hljs-built_in">print</span> <span class="hljs-string">&quot;&lt;table&gt;&quot;</span> }
{ <span class="hljs-built_in">printf</span> <span class="hljs-string">&quot;&lt;tr&gt;&lt;td&gt;%s&lt;/td&gt;&lt;td&gt;%s&lt;/td&gt;&lt;/tr&gt;\n&quot;</span>, <span class="hljs-variable">$1</span>, <span class="hljs-variable">$2</span> }
END { <span class="hljs-built_in">print</span> <span class="hljs-string">&quot;&lt;/table&gt;&quot;</span> }
@@

&lt;table&gt;
&lt;tr&gt;&lt;td&gt;Jennifer Whalen&lt;/td&gt;&lt;td&gt;<span class="hljs-number">010</span>-<span class="hljs-number">8129</span>-<span class="hljs-number">4728</span>&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;Donald OConnell&lt;/td&gt;&lt;td&gt;<span class="hljs-number">010</span>-<span class="hljs-number">3512</span>-<span class="hljs-number">4623</span>&lt;/td&gt;&lt;/tr&gt;
. . . 
. . . 
-------------------------------------------------------

$ cat &lt;&lt;\EOF | m4             $ m4 &lt;&lt;\EOF                   $ &lt;&lt;\EOF m4
define(foo, world)dnl         define(foo, world)dnl         define(foo, world)dnl
define(foo, m4)               define(foo, m4)               define(foo, m4)
hello world macro !           hello world macro !           hello world macro !
EOF                           EOF                           EOF

hello m4 macro !              hello m4 macro !              hello m4 macro !
</code></pre>
<h4 id="&#xC5F0;&#xC0B0;&#xC790;&#xB85C;-&#xBA85;&#xB839;-&#xC5F0;&#xACB0;&#xD558;&#xAE30;"><code>&amp;&amp;</code> &#xC5F0;&#xC0B0;&#xC790;&#xB85C; &#xBA85;&#xB839; &#xC5F0;&#xACB0;&#xD558;&#xAE30;</h4>
<pre><code class="lang-bash">$ <span class="hljs-built_in">cd</span> `mktemp <span class="hljs-operator">-d</span>` &amp;&amp; gcc -xc -static - &lt;&lt;\@ &amp;&amp; docker build <span class="hljs-operator">-f</span> - &lt;&lt;\@@ . -t $$ \
&amp;&amp; docker run --rm <span class="hljs-variable">$_</span> &amp;&amp; docker rmi <span class="hljs-variable">$_</span> &amp;&amp; <span class="hljs-built_in">cd</span> - &amp;&amp; rm -rf <span class="hljs-variable">$OLDPWD</span>
<span class="hljs-comment">#include &lt;stdio.h&gt;</span>
int <span class="hljs-function"><span class="hljs-title">main</span></span>() {
    puts(<span class="hljs-string">&quot;\nhello heredoc !!!\n&quot;</span>);
    <span class="hljs-built_in">return</span> <span class="hljs-number">0</span>;
}
@
FROM scratch
COPY a.out /
ENTRYPOINT [<span class="hljs-string">&quot;/a.out&quot;</span>]
@@

<span class="hljs-comment">############  &#xC2E4;&#xD589; &#xACB0;&#xACFC;  ###########</span>

Sending build context to Docker daemon  <span class="hljs-number">868.4</span>kB    <span class="hljs-comment"># docker build</span>
Step <span class="hljs-number">1</span>/<span class="hljs-number">3</span> : FROM scratch
 ---&gt; 
Step <span class="hljs-number">2</span>/<span class="hljs-number">3</span> : COPY a.out /
 ---&gt; bbb48d00ab4b
Step <span class="hljs-number">3</span>/<span class="hljs-number">3</span> : ENTRYPOINT [<span class="hljs-string">&quot;/a.out&quot;</span>]
 ---&gt; Running <span class="hljs-keyword">in</span> <span class="hljs-number">9</span>bd94749f43a
Removing intermediate container <span class="hljs-number">9</span>bd94749f43a
 ---&gt; a3b234463237
Successfully built a3b234463237
Successfully tagged <span class="hljs-number">23837</span>:latest

hello heredoc !!!                                  <span class="hljs-comment"># docker run</span>

Untagged: <span class="hljs-number">23837</span>:latest                             <span class="hljs-comment"># docker rmi</span>
Deleted: sha256:a3b2344632374c716a5938e51aa6031771879f8f1215280f346b8d23cb2e8a1e
Deleted: sha256:bbb48d00ab4bb42134e47ef459c490c5ef5c02436d68a75220c33378b2700f3c
Deleted: sha256:d6e7c19c556bee448f900f3133a0723cf286282574d1056ed62feae5d0069065
</code></pre>
<h4 id="here-document-&#xB97C;-&#xC774;&#xC6A9;&#xD55C;-&#xBCC0;&#xC218;&#xAC12;-&#xC124;&#xC815;">Here document &#xB97C; &#xC774;&#xC6A9;&#xD55C; &#xBCC0;&#xC218;&#xAC12; &#xC124;&#xC815;</h4>
<pre><code class="lang-bash">$ AA=$( cat &lt;&lt;EOF
&gt; <span class="hljs-string">&apos;here&apos;</span>
&gt; <span class="hljs-string">&quot;document&quot;</span>
&gt; EOF           <span class="hljs-comment"># &#xB9C8;&#xC9C0;&#xB9C9; &#xC904;&#xC740; &#xAD6C;&#xBD84;&#xC790; &#xC678;&#xC5D0; &#xB2E4;&#xB978; &#xBB38;&#xC790;&#xAC00; &#xC624;&#xBA74; &#xC548;&#xB41C;&#xB2E4;. (&#xACF5;&#xBC31;&#xB3C4; &#xC548;&#xB428;)</span>
&gt; )

$ <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;<span class="hljs-variable">$AA</span>&quot;</span>
<span class="hljs-string">&apos;here&apos;</span>
<span class="hljs-string">&quot;document&quot;</span>
............................................................

<span class="hljs-comment"># &#xBA85;&#xB839;&#xCE58;&#xD658;&#xC774; &#xC77C;&#xC5B4;&#xB098;&#xC57C; &#xD558;&#xBBC0;&#xB85C; END &#xAD6C;&#xBD84;&#xC790;&#xB97C; escape &#xD558;&#xBA74; &#xC548;&#xB429;&#xB2C8;&#xB2E4;.</span>
$ IFS=, <span class="hljs-built_in">read</span> AA BB CC &lt;&lt;END
$( awk <span class="hljs-string">&apos;BEGIN{ print &quot;100,,*&quot; }&apos;</span> )      <span class="hljs-comment"># &#xB450; &#xBC88;&#xC9F8; &#xAC12;&#xC740; empty</span>
END

$ <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;<span class="hljs-variable">$AA</span> : <span class="hljs-variable">$BB</span> : <span class="hljs-variable">$CC</span>&quot;</span>
<span class="hljs-number">100</span> :  : *
</code></pre>
<p>&#xB2E4;&#xC74C;&#xC740; html &#xC5D0;&#xC11C; <code>&lt;head&gt;</code> &#xD0DC;&#xADF8; &#xC544;&#xB798;&#xC5D0; javascript &#xCF54;&#xB4DC;&#xB97C; &#xCD94;&#xAC00;&#xD558;&#xAE30; &#xC704;&#xD55C; &#xAC83;&#xC778;&#xB370;&#xC694;.
&#xBA3C;&#xC800; here document &#xC5D0; &#xCF54;&#xB4DC;&#xB97C; &#xBD99;&#xC5EC;&#xB123;&#xAE30; &#xD55C; &#xD6C4; sed &#xBA85;&#xB839; &#xC2E4;&#xD589;&#xC5D0; &#xD544;&#xC694;&#xD55C; escape &#xCC98;&#xB9AC;&#xB97C; &#xD558;&#xC5EC; &#xBCC0;&#xC218;&#xC5D0; &#xB300;&#xC785;&#xD569;&#xB2C8;&#xB2E4;.</p>
<blockquote>
<p>&#xC880; &#xB354; &#xC790;&#xC138;&#xD55C; &#xB0B4;&#xC6A9;&#xC740; <a href="https://mug896.github.io/sed-stream-editor/multiple_lines.html#quiz" target="_blank">&#xC5EC;&#xAE30;</a>
&#xB97C; &#xCC38;&#xC870;&#xD558;&#xC138;&#xC694;</p>
</blockquote>
<pre><code class="lang-bash">GOOGLE_ANAL=$( cat &lt;&lt;\EOF | sed -z <span class="hljs-operator">-e</span> <span class="hljs-string">&apos;s#\([&amp;\#]\)#\\\1#g&apos;</span> <span class="hljs-operator">-e</span> <span class="hljs-string">&apos;s#\n#\\n#g&apos;</span> 
&lt;head&gt;

&lt;!-- Global site tag (gtag.js) - Google Analytics --&gt;
&lt;script async src=<span class="hljs-string">&quot;https://www.googletagmanager.com/gtag/js?id=UA-1234&quot;</span>&gt;&lt;/script&gt;
&lt;script&gt;
  window.dataLayer = window.dataLayer || [];
  <span class="hljs-keyword">function</span> <span class="hljs-function"><span class="hljs-title">gtag</span></span>(){dataLayer.push(arguments);}
  gtag(<span class="hljs-string">&apos;js&apos;</span>, new Date());
  gtag(<span class="hljs-string">&apos;config&apos;</span>, <span class="hljs-string">&apos;UA-1234&apos;</span>);
&lt;/script&gt;
EOF
)
<span class="hljs-comment"># escape &#xCC98;&#xB9AC;&#xAC00; &#xC644;&#xB8CC;&#xB41C; &#xBCC0;&#xC218;&#xAC12;&#xC744; &#xC774;&#xC6A9;&#xD574; sed &#xBA85;&#xB839; &#xC2E4;&#xD589;</span>
sed -z -i <span class="hljs-string">&apos;s#&lt;head&gt;#&apos;</span><span class="hljs-string">&quot;<span class="hljs-variable">${GOOGLE_ANAL}</span>&quot;</span><span class="hljs-string">&apos;#&apos;</span> *.html
</code></pre>
<p>&#xD604;&#xC7AC; &#xAC01; cpu core &#xC5D0; &#xBC14;&#xC6B4;&#xB4DC;&#xB41C; &#xC2A4;&#xB808;&#xB4DC; &#xAC1C;&#xC218;&#xB97C; &#xC2E4;&#xC2DC;&#xAC04;&#xC73C;&#xB85C; &#xBCF4;&#xAE30;</p>
<pre><code class="lang-bash"><span class="hljs-comment"># ps &#xBA85;&#xB839;&#xC5D0;&#xC11C; psr &#xC740; &#xD604;&#xC7AC; &#xC2A4;&#xB808;&#xB4DC;&#xAC00; &#xBC14;&#xC6B4;&#xB4DC;&#xB41C; cpu core &#xB97C; &#xB9D0;&#xD558;&#xACE0;</span>
<span class="hljs-comment"># &#xB4A4;&#xC5D0; &apos;=&apos; &#xB294; ps &#xBA85;&#xB839;&#xC774; &#xD0C0;&#xC774;&#xD2C0;&#xC744; &#xD45C;&#xC2DC;&#xD558;&#xC9C0; &#xC54A;&#xAC8C; &#xD569;&#xB2C8;&#xB2E4;.</span>
<span class="hljs-comment"># &#xCD9C;&#xB825; &#xACB0;&#xACFC;&#xAC00; &#xC2E4;&#xC81C; &#xCF54;&#xC5B4; &#xC218; &#xBCF4;&#xB2E4; &#xB9CE;&#xAC8C; &#xB098;&#xC624;&#xB294; &#xC774;&#xC720;&#xB294; Hyper-Threading &#xB54C;&#xBB38;&#xC785;&#xB2C8;&#xB2E4;.</span>

$ watch -td -n1 <span class="hljs-string">&quot;<span class="hljs-variable">$( cat &lt;&lt;\EOF
ps axH -o psr= |
awk &apos;{a[$1]++} END { 
    for (i in a)</span> { printf &quot;</span>cpu%-<span class="hljs-number">6</span>d<span class="hljs-string">&quot;,i }; print &quot;</span><span class="hljs-string">&quot;;
    for (i in a) { printf &quot;</span>%-<span class="hljs-number">9</span>d<span class="hljs-string">&quot;, a[i] }; print &quot;</span><span class="hljs-string">&quot; }&apos; 
EOF
)&quot;</span>
cpu0     cpu1     cpu2     cpu3     cpu4     cpu5     cpu6     cpu7     
<span class="hljs-number">289</span>      <span class="hljs-number">232</span>      <span class="hljs-number">269</span>      <span class="hljs-number">198</span>      <span class="hljs-number">260</span>      <span class="hljs-number">214</span>      <span class="hljs-number">279</span>      <span class="hljs-number">215</span>
</code></pre>
<h4 id="sh-c--&#xB610;&#xB294;-bash-c--&#xC0AC;&#xC6A9;&#xC2DC;-multiline-&#xBA85;&#xB839;-&#xC791;&#xC131;&#xBC95;">sh -c ... &#xB610;&#xB294; bash -c ... &#xC0AC;&#xC6A9;&#xC2DC; multi-line &#xBA85;&#xB839; &#xC791;&#xC131;&#xBC95;</h4>
<p>&#xBCF4;&#xD1B5; <code>sh -c ...</code> &#xD615;&#xD0DC;&#xB85C; &#xBA85;&#xB839;&#xC744; &#xC2E4;&#xD589;&#xD560; &#xB54C;&#xB294; quote &#xC744; &#xD558;&#xACE0; single-line &#xC73C;&#xB85C; &#xC791;&#xC131;&#xD558;&#xB294;&#xB370;&#xC694;.
here document &#xB97C; &#xC0AC;&#xC6A9;&#xD558;&#xBA74; multi-line &#xBA85;&#xB839;&#xC744; &#xC791;&#xC131;&#xD560; &#xC218; &#xC788;&#xACE0;
quotes &#xB3C4; single, double quotes &#xBAA8;&#xB450; escape &#xC5C6;&#xC774; &#xC0AC;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash">$ CMD=$( cat &lt;&lt;\EOF                        $ bash -c <span class="hljs-string">&quot;<span class="hljs-variable">$( cat &lt;&lt;\EOF
AA=100                                     AA=100
echo -e &quot;double quotes\n$AA&quot;               echo -e &quot;double quotes\n$AA&quot;
echo &apos;single quotes\n$AA&apos;                  echo &apos;single quotes\n$AA&apos;
cat &lt;&lt;\@                                   cat &lt;&lt;\@
&apos;here&apos;                                     &apos;here&apos;
&quot;document&quot;                                 &quot;document&quot;
@                                          @
EOF                                        EOF
)</span>                                          )&quot;</span>

$ bash -c <span class="hljs-string">&quot;<span class="hljs-variable">$CMD</span>&quot;</span>                           double quotes
double quotes                              <span class="hljs-number">100</span>
<span class="hljs-number">100</span>                                        single quotes\n<span class="hljs-variable">$AA</span>
single quotes\n<span class="hljs-variable">$AA</span>                         <span class="hljs-string">&apos;here&apos;</span>
<span class="hljs-string">&apos;here&apos;</span>                                     <span class="hljs-string">&quot;document&quot;</span>
<span class="hljs-string">&quot;document&quot;</span>
</code></pre>
<h4 id="while-&#xBB38;&#xC758;-&#xC785;&#xB825;&#xC73C;&#xB85C;-&#xC0AC;&#xC6A9;&#xD558;&#xAE30;">while &#xBB38;&#xC758; &#xC785;&#xB825;&#xC73C;&#xB85C; &#xC0AC;&#xC6A9;&#xD558;&#xAE30;</h4>
<pre><code class="lang-bash">$ <span class="hljs-keyword">while</span> <span class="hljs-built_in">read</span> -r line; <span class="hljs-keyword">do</span>
&gt;       <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;<span class="hljs-variable">$line</span>&quot;</span>
&gt; <span class="hljs-keyword">done</span> &lt;&lt;END
&gt; here
&gt; document
&gt; END
here
document
</code></pre>
<h4 id="leading-tab-&#xC744;-&#xC774;&#xC6A9;&#xD55C;-&#xB4E4;&#xC5EC;&#xC4F0;&#xAE30;">Leading tab &#xC744; &#xC774;&#xC6A9;&#xD55C; &#xB4E4;&#xC5EC;&#xC4F0;&#xAE30;</h4>
<p>here document &#xAE30;&#xD638;&#xB85C; <code>&lt;&lt;-</code> &#xB97C; &#xC774;&#xC6A9;&#xD558;&#xBA74; &#xB0B4;&#xC6A9;&#xC744; &#xC791;&#xC131;&#xD560; &#xB54C; leading tab &#xC744; &#xC0AC;&#xC6A9;&#xD558;&#xC5EC;
&#xB4E4;&#xC5EC; &#xC4F0;&#xAE30;&#xB97C; &#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;. &#xCD9C;&#xB825;&#xC2DC;&#xC5D0;&#xB294; leading tab &#xC774; &#xC81C;&#xAC70;&#xB418;&#xC5B4; &#xCD9C;&#xB825;&#xB429;&#xB2C8;&#xB2E4;.</p>
<blockquote>
<p>&#xBA85;&#xB839;&#xBB38; &#xC791;&#xC131;&#xC2DC; tab &#xBB38;&#xC790; &#xC785;&#xB825;&#xC740; <code>Ctrl-v</code> + <code>tab</code> &#xC73C;&#xB85C; &#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
</blockquote>
<pre><code class="lang-bash">$ <span class="hljs-keyword">if</span> <span class="hljs-literal">true</span>; <span class="hljs-keyword">then</span>
&gt;       cat &lt;&lt;EOF
&gt;       here 
&gt;       document
&gt;       with tab
&gt; EOF
&gt; <span class="hljs-keyword">fi</span>
    here         <span class="hljs-comment"># &#xCD9C;&#xB825;&#xC5D0; leading tab &#xC774; &#xD3EC;&#xD568;&#xB428; </span>
    document
    with tab

<span class="hljs-comment"># &apos;&lt;&lt;&apos; &#xAE30;&#xD638; &#xB300;&#xC2E0;&#xC5D0; &apos;&lt;&lt;-&apos; &#xB97C; &#xC0AC;&#xC6A9;</span>
$ <span class="hljs-keyword">if</span> <span class="hljs-literal">true</span>; <span class="hljs-keyword">then</span>        
&gt;       cat &lt;&lt;-EOF
&gt;       here
&gt;       document
&gt;       with tab
&gt;       EOF          <span class="hljs-comment"># &#xC885;&#xB8CC; &#xAD6C;&#xBD84;&#xC790;&#xB3C4; &#xB4E4;&#xC5EC;&#xC4F0;&#xAE30; &#xAC00;&#xB2A5;</span>
&gt; <span class="hljs-keyword">fi</span>
here                 <span class="hljs-comment"># &#xCD9C;&#xB825;&#xC740; leading tab &#xC774; &#xC81C;&#xAC70;&#xB418;&#xC5B4; &#xCD9C;&#xB825;&#xB429;&#xB2C8;&#xB2E4;.</span>
document
with tab
</code></pre>
<h4 id="&#xC911;&#xCCA9;-&#xC0AC;&#xC6A9;">&#xC911;&#xCCA9; &#xC0AC;&#xC6A9;</h4>
<pre><code class="lang-bash">$ cat &lt;&lt;EOF1 &lt;&lt;EOF2                          $ FOO=$( cat &lt;&lt;\EOF1
<span class="hljs-string">&apos;hello&apos;</span>                                      cat &lt;&lt;\EOF2
<span class="hljs-string">&quot;world&quot;</span>                                      <span class="hljs-string">&apos;hello&apos;</span>
EOF1                                         <span class="hljs-string">&quot;world&quot;</span>
                                             EOF2
message start                                EOF1
$( &lt; /dev/stdin )                            )
message end                                  
EOF2                                         $ <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;<span class="hljs-variable">$FOO</span>&quot;</span>
                                             cat &lt;&lt;\EOF2
<span class="hljs-comment">######  &#xC2E4;&#xD589; &#xACB0;&#xACFC;  ######                      &apos;hello&apos;</span>
                                             <span class="hljs-string">&quot;world&quot;</span>
message start                                EOF2
<span class="hljs-string">&apos;hello&apos;</span>                                      
<span class="hljs-string">&quot;world&quot;</span>                                      $ <span class="hljs-built_in">eval</span> <span class="hljs-string">&quot;<span class="hljs-variable">$FOO</span>&quot;</span>
message end                                  <span class="hljs-string">&apos;hello&apos;</span>
                                             <span class="hljs-string">&quot;world&quot;</span>
</code></pre>
<h2 id="here-string">&lt;&lt;&lt; here string</h2>
<p>here string &#xC740; <code>&lt;&lt;&lt;</code> &#xC6B0;&#xCE21;&#xC5D0; &#xD558;&#xB098;&#xC758; &#xC778;&#xC218;&#xB9CC;&#xC744; &#xAC16;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xD398;&#xC774;&#xC9C0;&#xC758; &#xCC98;&#xC74C; &#xADF8;&#xB9BC;&#xC5D0;&#xC11C; &#xBCFC; &#xC218; &#xC788;&#xB4EF;&#xC774; &#xAC12;&#xC774; &#xC784;&#xC2DC; &#xD30C;&#xC77C; &#xD615;&#xD0DC;&#xB85C; &#xC804;&#xB2EC;&#xB418;&#xAE30; &#xB54C;&#xBB38;&#xC5D0; 
<code>&lt;&lt;&lt; $(command ...)</code> &#xB294; &#xC0AC;&#xC2E4;&#xC0C1; <code>&lt; /tmp/file</code> &#xC640; &#xAC19;&#xAC8C;&#xB418;&#xACE0;
&#xC774;&#xB54C; file &#xB0B4;&#xC6A9;&#xC740; <code>$(command ...)</code> &#xC758; &#xD655;&#xC7A5; &#xACB0;&#xACFC;&#xAC00; &#xB429;&#xB2C8;&#xB2E4;.
&#xB530;&#xB77C;&#xC11C; &#xBA85;&#xB839; &#xCE58;&#xD658;&#xC774;&#xB098; &#xBCC0;&#xC218;&#xAC00; &#xC0AC;&#xC6A9;&#xB420; &#xACBD;&#xC6B0; &#xB530;&#xB85C; quotes &#xC744; &#xD558;&#xC9C0; &#xC54A;&#xC544;&#xB3C4; 
&#xD3EC;&#xBA67;&#xC774; &#xC720;&#xC9C0;&#xB418;&#xACE0; globbing &#xC774; &#xBC1C;&#xC0DD;&#xD558;&#xC9C0; &#xC54A;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash"><span class="hljs-comment"># quote &#xD558;&#xC9C0; &#xC54A;&#xC544;&#xB3C4; &#xD3EC;&#xBA67;&#xC774; &#xC720;&#xC9C0;&#xB41C;&#xB2E4;.</span>
$ cat &lt;&lt;&lt; $( <span class="hljs-built_in">echo</span> <span class="hljs-operator">-e</span> <span class="hljs-string">&quot;hello\nhere        string&quot;</span> )
hello
here        string

<span class="hljs-comment"># globbing &#xC774; &#xBC1C;&#xC0DD;&#xD558;&#xC9C0; &#xC54A;&#xB294;&#xB2E4;.</span>
$ cat &lt;&lt;&lt; *
*

$ <span class="hljs-keyword">while</span> <span class="hljs-built_in">read</span> file; <span class="hljs-keyword">do</span> <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;<span class="hljs-variable">$file</span>&quot;</span>; <span class="hljs-keyword">done</span> &lt;&lt;&lt; $(find .)
.
./&#xC258; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8; &#xD14C;&#xC2A4;&#xD305;.txt
./<span class="hljs-number">2013</span>-<span class="hljs-number">03</span>-<span class="hljs-number">19</span> <span class="hljs-number">154412</span>.csv
./ReadObject.class
./ReadObject.java
</code></pre>
<p>&#xBA85;&#xB839;&#xC758; &#xCD9C;&#xB825;&#xC744; read &#xBA85;&#xB839;&#xC744; &#xC774;&#xC6A9;&#xD574; &#xBCC0;&#xC218;&#xAC12;&#xC5D0; &#xC124;&#xC815;&#xD558;&#xB824;&#xACE0; &#xD560; &#xB54C;
&#xD30C;&#xC774;&#xD504;&#xB97C; &#xC0AC;&#xC6A9;&#xD558;&#xBA74; subshell &#xB85C; &#xC778;&#xD574; &#xC124;&#xC815;&#xB41C; &#xBCC0;&#xC218;&#xC758; &#xAC12;&#xC744; &#xC720;&#xC9C0;&#xD560; &#xC218;&#xAC00; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xC774;&#xB54C; here string &#xC744; &#xC774;&#xC6A9;&#xD558;&#xBA74; &#xD604;&#xC7AC; shell &#xC5D0;&#xC11C; &#xC2E4;&#xD589;&#xB418;&#xC5B4; &#xBB38;&#xC81C;&#xB97C; &#xD574;&#xACB0;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash"><span class="hljs-comment"># read &#xBA85;&#xB839;&#xC774; &apos;|&apos; &#xB85C;&#xC778;&#xD574; subshell &#xC5D0;&#xC11C; &#xC2E4;&#xD589;&#xB418;&#xC5B4; &#xAC12;&#xC774; &#xD45C;&#xC2DC;&#xB418;&#xC9C0; &#xC54A;&#xB294;&#xB2E4;</span>
$ awk <span class="hljs-string">&apos;BEGIN { print &quot;here string test&quot; }&apos;</span> | <span class="hljs-built_in">read</span> v1 v2 v3
$ <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;<span class="hljs-variable">$v1</span> : <span class="hljs-variable">$v2</span> : <span class="hljs-variable">$v3</span>&quot;</span>
 :  : 

<span class="hljs-comment"># &apos;&lt;&lt;&lt;&apos; &#xB294; &#xD604;&#xC7AC; shell &#xC5D0;&#xC11C; &#xC2E4;&#xD589;&#xB418;&#xC5B4; &#xC815;&#xC0C1;&#xC801;&#xC73C;&#xB85C; &#xAC12;&#xC744;&#xCD9C;&#xB825;.</span>
$ <span class="hljs-built_in">read</span> v1 v2 v3 &lt;&lt;&lt; $( awk <span class="hljs-string">&apos;BEGIN{ print &quot;here string test&quot; }&apos;</span> )
$ <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;<span class="hljs-variable">$v1</span> : <span class="hljs-variable">$v2</span> : <span class="hljs-variable">$v3</span>&quot;</span>
here : string : <span class="hljs-built_in">test</span>

<span class="hljs-comment"># &#xBCC0;&#xC218;&#xAC12; &#xC911;&#xC5D0; empty &#xAC12;&#xC774; &#xC788;&#xC744; &#xACBD;&#xC6B0; IFS &#xB97C; &#xD65C;&#xC6A9;</span>
$ IFS=, <span class="hljs-built_in">read</span> AA BB CC &lt;&lt;&lt; $( awk <span class="hljs-string">&apos;BEGIN{ print &quot;100,,*&quot; }&apos;</span> )
$ <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;<span class="hljs-variable">$AA</span> : <span class="hljs-variable">$BB</span> : <span class="hljs-variable">$CC</span>&quot;</span>
<span class="hljs-number">100</span> :  : *
</code></pre>
<p>here string &#xC740; &#xB9C8;&#xC9C0;&#xB9C9;&#xC5D0; &#xC790;&#xB3D9;&#xC73C;&#xB85C; newline &#xC744; &#xBD99;&#xC785;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash">$ od <span class="hljs-operator">-a</span> &lt;&lt;&lt; <span class="hljs-string">&apos;123&apos;</span>
<span class="hljs-number">0000000</span>   <span class="hljs-number">1</span>   <span class="hljs-number">2</span>   <span class="hljs-number">3</span>  nl
<span class="hljs-number">0000004</span>
</code></pre>
<h1 id="quiz">Quiz</h1>
<p>&#xC258; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8;&#xC5D0; &#xBC14;&#xC774;&#xB108;&#xB9AC; &#xD30C;&#xC77C;&#xC744; &#xC800;&#xC7A5;&#xD558;&#xC5EC; &#xC2E4;&#xD589;&#xD558;&#xB824;&#xBA74; &#xC5B4;&#xB5BB;&#xAC8C; &#xD560;&#xAE4C;&#xC694;?</p>
<h4 id="base64-&#xB97C;-&#xC774;&#xC6A9;&#xD558;&#xB294;-&#xBC29;&#xBC95;">base64 &#xB97C; &#xC774;&#xC6A9;&#xD558;&#xB294; &#xBC29;&#xBC95;</h4>
<p>base64 &#xBA85;&#xB839;&#xC744; &#xC774;&#xC6A9;&#xD558;&#xBA74; binary &#xD30C;&#xC77C;&#xC774; &#xD14D;&#xC2A4;&#xD2B8;&#xB85C; &#xBCC0;&#xD658;&#xB418;&#xBBC0;&#xB85C; &#xC774; &#xBC29;&#xBC95;&#xC740; binary &#xD30C;&#xC77C;&#xC744; &#xC804;&#xC1A1;&#xD560; &#xC218; &#xC5C6;&#xB294; &#xD658;&#xACBD;&#xC5D0;&#xC11C; &#xC774;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<p><b>1</b> . &#xBA3C;&#xC800; base64 &#xBA85;&#xB839;&#xC744; &#xC774;&#xC6A9;&#xD558;&#xC5EC; binary &#xD30C;&#xC77C;&#xC744; &#xD14D;&#xC2A4;&#xD2B8;&#xB85C; &#xBCC0;&#xD658;&#xD569;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash">$ base64 binaryCommand &gt; test.sh
</code></pre>
<p><b>2</b> . test.sh &#xD30C;&#xC77C;&#xC744; &#xD14D;&#xC2A4;&#xD2B8; &#xC5D0;&#xB514;&#xD130;&#xB85C; &#xC5F4;&#xC5B4; &#xBCF4;&#xBA74; base64 &#xB85C; &#xC778;&#xCF54;&#xB529;&#xB41C; &#xB370;&#xC774;&#xD130;&#xAC00; &#xC800;&#xC7A5;&#xB418;&#xC5B4;&#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xB2E4;&#xC74C;&#xACFC; &#xAC19;&#xC774; &#xC218;&#xC815;&#xD558;&#xC5EC; &#xC0AC;&#xC6A9;&#xD558;&#xBA74; &#xB429;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash"><span class="hljs-shebang">#!/bin/bash</span>
<span class="hljs-comment"># &#xBA3C;&#xC800; &#xC2DC;&#xC2A4;&#xD15C;&#xC774; &#xBC14;&#xC774;&#xB108;&#xB9AC; &#xBA85;&#xB839;&#xC744; &#xC2E4;&#xD589;&#xD560; &#xC218; &#xC788;&#xB294;&#xC9C0; &#xCCB4;&#xD06C;&#xD569;&#xB2C8;&#xB2E4;.</span>
[ <span class="hljs-string">&quot;<span class="hljs-variable">$(uname -mo)</span>&quot;</span> = <span class="hljs-string">&quot;x86_64 GNU/Linux&quot;</span> ] || { <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;binary can&apos;t execute&quot;</span>; <span class="hljs-built_in">exit</span> <span class="hljs-number">1</span> ;}

<span class="hljs-built_in">trap</span> <span class="hljs-string">&apos;rm -f &quot;$tmpFile&quot;&apos;</span> EXIT

<span class="hljs-built_in">echo</span> start...

tmpFile=`mktemp -p .`

base64 <span class="hljs-operator">-d</span> &gt; <span class="hljs-string">&quot;<span class="hljs-variable">$tmpFile</span>&quot;</span> &lt;&lt;\END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=
END

chmod +x <span class="hljs-string">&quot;<span class="hljs-variable">$tmpFile</span>&quot;</span> &amp;&amp; <span class="hljs-string">&quot;<span class="hljs-variable">$tmpFile</span>&quot;</span>

<span class="hljs-built_in">echo</span> end...
</code></pre>
<blockquote>
<p>base64 &#xBA85;&#xB839;&#xC740; &#xBC14;&#xC774;&#xB108;&#xB9AC; &#xD30C;&#xC77C;&#xC744; &#xD14D;&#xC2A4;&#xD2B8; &#xD30C;&#xC77C;&#xB85C; &#xBCC0;&#xD658;&#xD574; &#xC8FC;&#xB294; &#xC720;&#xD2F8;&#xC785;&#xB2C8;&#xB2E4;.<br>&#xBCC0;&#xD658;&#xD560;&#xB54C; 6 bits &#xB97C; 1 &#xBB38;&#xC790;&#xB85C; &#xBC14;&#xAFB8;&#xB294;&#xB370; &#xC774;&#xB54C; &#xC0AC;&#xC6A9;&#xD558;&#xB294; &#xBB38;&#xC790;&#xC14B;&#xC740; <code>A-Z</code>, <code>a-z</code>, <code>0-9</code>, <code>+</code>, <code>/</code> &#xCD1D; 64 &#xBB38;&#xC790; 
(2^6 = 64) &#xC785;&#xB2C8;&#xB2E4; ( &#xC774;&#xAC83;&#xC774; &#xBA85;&#xB839; &#xC774;&#xB984;&#xC5D0; &#xBD99;&#xC740; 64 &#xC758;&#xBBF8;&#xC785;&#xB2C8;&#xB2E4; ).
&#xC608;&#xB97C; &#xB4E4;&#xC5B4; 3 bytes ( 3 * 8 = 24 bits ) &#xB97C; &#xBCC0;&#xD658;&#xD560; &#xACBD;&#xC6B0; 
&#xACB0;&#xACFC;&#xC801;&#xC73C;&#xB85C; 4 &#xAC1C;&#xC758; &#xBB38;&#xC790;&#xAC00; ( 24 / 6 = 4 ) &#xC0DD;&#xACA8;&#xC11C; 4 bytes &#xAC00; &#xB418;&#xBBC0;&#xB85C; &#xC2E4;&#xC81C; &#xD30C;&#xC77C; &#xBCF4;&#xB2E4; &#xC57D; 33% &#xC815;&#xB3C4; &#xD06C;&#xAE30;&#xAC00; &#xCEE4;&#xC9D1;&#xB2C8;&#xB2E4;.
base64 &#xB97C; &#xC0AC;&#xC6A9;&#xD558;&#xC9C0; &#xC54A;&#xACE0; hex &#xB85C; &#xBC14;&#xAFBC;&#xB2E4;&#xBA74; 1 byte &#xB2F9; 2 &#xBB38;&#xC790;&#xAC00; &#xD544;&#xC694;&#xD558;&#xBBC0;&#xB85C; &#xD30C;&#xC77C; &#xC0AC;&#xC774;&#xC988;&#xAC00; 2 &#xBC30;&#xAC00; &#xB418;&#xACA0;&#xC8E0;.</p>
</blockquote>
<h4 id="binary-&#xD30C;&#xC77C;&#xC744;-&#xC9C1;&#xC811;-append-&#xD558;&#xB294;-&#xBC29;&#xBC95;">binary &#xD30C;&#xC77C;&#xC744; &#xC9C1;&#xC811; append &#xD558;&#xB294; &#xBC29;&#xBC95;</h4>
<p>&#xC774; &#xBC29;&#xBC95;&#xC740; base64 &#xC778;&#xCF54;&#xB529;&#xC744; &#xAC70;&#xCE58;&#xC9C0; &#xC54A;&#xACE0; binary &#xD30C;&#xC77C;&#xC744; &#xC9C1;&#xC811; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8; &#xD30C;&#xC77C;&#xC5D0; append &#xD569;&#xB2C8;&#xB2E4;.
binary &#xD30C;&#xC77C;&#xC740; &#xC555;&#xCD95;&#xD30C;&#xC77C;, &#xC2E4;&#xD589;&#xD30C;&#xC77C;, &#xC774;&#xBBF8;&#xC9C0;, &#xB3D9;&#xC601;&#xC0C1; &#xC5B4;&#xB5A4; &#xC885;&#xB958;&#xB358; &#xC0C1;&#xAD00;&#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xC778;&#xCF54;&#xB529;&#xC5D0; &#xC758;&#xD574; &#xD30C;&#xC77C; &#xC0AC;&#xC774;&#xC988;&#xAC00; &#xCEE4;&#xC9C0;&#xC9C0; &#xC54A;&#xC73C;&#xBBC0;&#xB85C; &#xD504;&#xB85C;&#xADF8;&#xB7A8;&#xC744; &#xC258; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8;&#xB97C; &#xC774;&#xC6A9;&#xD574; &#xBC30;&#xD3EC;&#xD560;&#xB54C; &#xC8FC;&#xB85C; &#xC774; &#xBC29;&#xBC95;&#xC744; &#xC0AC;&#xC6A9;&#xD569;&#xB2C8;&#xB2E4;.</p>
<p><b>1</b> . &#xBA3C;&#xC800; append &#xD560; binary &#xD30C;&#xC77C;&#xC758; &#xC0AC;&#xC774;&#xC988;&#xB97C; &#xAD6C;&#xD569;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash">$ <span class="hljs-built_in">stat</span> -c %s binaryFile
<span class="hljs-number">512</span>
</code></pre>
<p><b>2</b> . &#xADF8;&#xB2E4;&#xC74C; &#xC544;&#xB798;&#xC640; &#xAC19;&#xC740;  &#xB0B4;&#xC6A9;&#xC758; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8; &#xD30C;&#xC77C;&#xC744; &#xBA3C;&#xC800; &#xC791;&#xC131;&#xD569;&#xB2C8;&#xB2E4;.
&#xC774;&#xBC88;&#xC5D0;&#xB294; <code>sh</code> &#xB85C; &#xC791;&#xC131;&#xD558;&#xC600;&#xC2B5;&#xB2C8;&#xB2E4;.
base64 &#xB97C; &#xC774;&#xC6A9;&#xD558;&#xB294; &#xBC29;&#xBC95;&#xC5D0;&#xC11C;&#xB294; &#xC5C6;&#xC5C8;&#xB358; tail &#xBA85;&#xB839;&#xC774; &#xC0AC;&#xC6A9;&#xB41C; &#xAC83;&#xC744; &#xBCFC; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xC774; &#xBD80;&#xBD84;&#xC774; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8; &#xD30C;&#xC77C;&#xC5D0; append &#xB41C; binary &#xD30C;&#xC77C;&#xC744; &#xCD94;&#xCD9C;&#xD558;&#xB294; &#xACFC;&#xC815;&#xC785;&#xB2C8;&#xB2E4;.
&#xADF8;&#xB9AC;&#xACE0; &#xB9C8;&#xC9C0;&#xB9C9;&#xC5D0;&#xB294; &#xBC18;&#xB4DC;&#xC2DC; exit &#xBA85;&#xB839;&#xC744; &#xC0AC;&#xC6A9;&#xD574;&#xC11C; &#xC885;&#xB8CC;&#xD574;&#xC57C; &#xD569;&#xB2C8;&#xB2E4;.
&#xADF8;&#xB807;&#xC9C0; &#xC54A;&#xC73C;&#xBA74; &#xC2E4;&#xD589;&#xC774; append &#xB41C; &#xD30C;&#xC77C;&#xAE4C;&#xC9C0; &#xB118;&#xC5B4;&#xAC11;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash"><span class="hljs-shebang">#!/bin/sh</span>
[ <span class="hljs-string">&quot;<span class="hljs-variable">$(uname -mo)</span>&quot;</span> = <span class="hljs-string">&quot;x86_64 GNU/Linux&quot;</span> ] || { <span class="hljs-built_in">echo</span> <span class="hljs-string">&quot;binary can&apos;t execute&quot;</span>; <span class="hljs-built_in">exit</span> <span class="hljs-number">1</span> ;}

<span class="hljs-built_in">trap</span> <span class="hljs-string">&apos;exit&apos;</span> HUP INT QUIT TERM
<span class="hljs-built_in">trap</span> <span class="hljs-string">&apos;rm -f &quot;$tmpFile&quot;&apos;</span> EXIT

scriptFile=`readlink <span class="hljs-operator">-e</span> <span class="hljs-variable">$0</span>`

tmpFile=`mktemp`

<span class="hljs-comment"># tail &#xBA85;&#xB839;&#xC73C;&#xB85C; append &#xB41C; binary file &#xC744; &#xCD94;&#xCD9C;</span>
tail -c <span class="hljs-number">512</span> <span class="hljs-string">&quot;<span class="hljs-variable">$scriptFile</span>&quot;</span> &gt; <span class="hljs-string">&quot;<span class="hljs-variable">$tmpFile</span>&quot;</span>
<span class="hljs-comment"># &#xB9CC;&#xC57D;&#xC5D0; append &#xB41C; &#xD30C;&#xC77C;&#xC774; tar &#xC555;&#xCD95; &#xD30C;&#xC77C;&#xC774;&#xB77C;&#xBA74;</span>
<span class="hljs-comment"># cd `mktemp -d` &amp;&amp; tail -c 512 &quot;$scriptFile&quot; | tar xvz</span>

chmod +x <span class="hljs-string">&quot;<span class="hljs-variable">$tmpFile</span>&quot;</span> &amp;&amp; <span class="hljs-string">&quot;<span class="hljs-variable">$tmpFile</span>&quot;</span>

<span class="hljs-comment"># &#xB9C8;&#xC9C0;&#xB9C9;&#xC740; &#xBC18;&#xB4DC;&#xC2DC; exit &#xBA85;&#xB839;&#xC73C;&#xB85C; &#xC885;&#xB8CC;</span>
<span class="hljs-built_in">exit</span>
</code></pre>
<p><b>3</b> . &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8; &#xD30C;&#xC77C; &#xC791;&#xC131;&#xC744; &#xC644;&#xB8CC;&#xD558;&#xC600;&#xC73C;&#xBA74; &#xC800;&#xC7A5;&#xD558;&#xACE0; &#xB098;&#xC640;&#xC11C; &#xB9C8;&#xC9C0;&#xB9C9;&#xC73C;&#xB85C; binary &#xD30C;&#xC77C;&#xC744; append &#xD569;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash">$ cat binaryFile &gt;&gt; test.sh
</code></pre>
<p>&#xD55C;&#xAC00;&#xC9C0; &#xCC38;&#xACE0; &#xD574;&#xC57C;&#xB420; &#xC0AC;&#xD56D;&#xC740; &#xD30C;&#xC77C;&#xC744; append &#xD558;&#xACE0; &#xB098;&#xC11C; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8; &#xD30C;&#xC77C;&#xC744; &#xB2E4;&#xC2DC; &#xC218;&#xC815;&#xD574;&#xC57C;&#xB420; &#xACBD;&#xC6B0;&#xAC00; &#xC0DD;&#xAE38;&#xC218; &#xC788;&#xB294;&#xB370;
&#xC774;&#xB54C; vi &#xC5D0;&#xB514;&#xD130;&#xB85C; &#xC218;&#xC815;&#xD558;&#xC5EC; &#xC800;&#xC7A5;&#xD558;&#xBA74; &#xD30C;&#xC77C;&#xC758; &#xB9C8;&#xC9C0;&#xB9C9; &#xBD80;&#xBD84;&#xC5D0; &#xC790;&#xB3D9;&#xC73C;&#xB85C; newline &#xC774; &#xBD99;&#xC5B4;&#xC11C; &#xBB38;&#xC81C;&#xAC00; &#xB429;&#xB2C8;&#xB2E4;.
&#xADF8;&#xB7EC;&#xBBC0;&#xB85C; &#xD30C;&#xC77C;&#xC744; &#xB2E4;&#xC2DC; &#xC218;&#xC815;&#xD560; &#xB54C;&#xB098; &#xC544;&#xB2C8;&#xBA74; &#xC774;&#xBBF8; &#xD30C;&#xC77C;&#xC758; &#xB9C8;&#xC9C0;&#xB9C9;&#xC5D0; newline &#xC774; &#xD3EC;&#xD568;&#xB418;&#xC5C8;&#xB2E4;&#xBA74; 
&#xB2E4;&#xC74C;&#xACFC; &#xAC19;&#xC740; &#xBC29;&#xBC95;&#xC73C;&#xB85C; &#xC885;&#xB8CC;&#xD558;&#xC5EC; newline &#xC744; &#xC81C;&#xAC70;&#xD560;&#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash"><span class="hljs-comment"># vi &#xB85C; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8; &#xC218;&#xC815;&#xC774; &#xC644;&#xB8CC;&#xB418;&#xC5C8;&#xC73C;&#xBA74; &#xB2E4;&#xC74C;&#xACFC; &#xAC19;&#xC774; &#xC885;&#xB8CC;&#xD574;&#xC57C; &#xD569;&#xB2C8;&#xB2E4;.</span>
: <span class="hljs-built_in">set</span> binary noeol
: wq
</code></pre>
<h1 id="2">2.</h1>
<p>binary &#xD30C;&#xC77C;&#xC744; hex &#xB85C; &#xBCC0;&#xACBD;&#xD558;&#xC5EC; &#xC800;&#xC7A5;&#xD558;&#xACE0; &#xB2E4;&#xC2DC; hex &#xD30C;&#xC77C;&#xC744; binary &#xD30C;&#xC77C;&#xB85C;
&#xB9CC;&#xB4E4;&#xB824;&#xBA74; &#xC5B4;&#xB5BB;&#xAC8C; &#xD560;&#xAE4C;&#xC694;?</p>
<p>/bin/date  &#xB97C; &#xB300;&#xC0C1;&#xC73C;&#xB85C; hex &#xBCC0;&#xD658;&#xC5D0; od &#xBA85;&#xB839;&#xC744;, &#xBCF5;&#xAD6C;&#xC5D0; xxd &#xBA85;&#xB839;&#xC744; &#xC0AC;&#xC6A9;&#xD558;&#xACA0;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash"><span class="hljs-comment"># binary &#xB97C; hex &#xB85C; &#xBCC0;&#xD658;</span>
<span class="hljs-comment"># od &#xBA85;&#xB839;&#xC758; -v &#xC635;&#xC158;&#xC740; &#xAC19;&#xC740; &#xB0B4;&#xC6A9;&#xC758; &#xB77C;&#xC778;&#xC774; &#xC5F0;&#xC774;&#xC5B4; &#xCD9C;&#xB825;&#xB420; &#xACBD;&#xC6B0; &apos;*&apos; &#xB85C; &#xD45C;&#xC2DC;&#xB418;&#xB294; &#xAC83;&#xC744; &#xBC29;&#xC9C0;&#xD569;&#xB2C8;&#xB2E4;.</span>
$ od -v -An -tx1 /bin/date &gt; date.hex
<span class="hljs-comment"># &#xB610;&#xB294;</span>
$ xxd -p /bin/date &gt; date.hex

$ head -<span class="hljs-number">2</span> date.hex
 <span class="hljs-number">7</span>f <span class="hljs-number">45</span> <span class="hljs-number">4</span>c <span class="hljs-number">46</span> <span class="hljs-number">02</span> <span class="hljs-number">01</span> <span class="hljs-number">01</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span>
 <span class="hljs-number">03</span> <span class="hljs-number">00</span> <span class="hljs-number">3</span>e <span class="hljs-number">00</span> <span class="hljs-number">01</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> a0 <span class="hljs-number">37</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span> <span class="hljs-number">00</span>

<span class="hljs-comment"># hex &#xD30C;&#xC77C;&#xC744; &#xB2E4;&#xC2DC; binary &#xB85C; &#xBCC0;&#xD658;</span>
$ xxd -r -p date.hex &gt; date2

<span class="hljs-comment"># &#xC6D0;&#xBCF8; binary &#xC640; &#xBE44;&#xAD50;</span>
$ cmp /bin/date date2

$ <span class="hljs-built_in">echo</span> $?
<span class="hljs-number">0</span>
.....................................................

$ cmp /bin/date &lt;(od -v -An -tx1 /bin/date | xxd -r -p)

$ <span class="hljs-built_in">echo</span> $?
<span class="hljs-number">0</span>
</code></pre>
<p>&#xD30C;&#xC77C;&#xC758; &#xD2B9;&#xC815; offset &#xC5D0;&#xC11C;&#xBD80;&#xD130; N &#xBC14;&#xC774;&#xD2B8; hex &#xCD94;&#xCD9C;</p>
<pre><code class="lang-bash"><span class="hljs-comment"># offset 2 &#xC5D0;&#xC11C;&#xBD80;&#xD130; 4 &#xBC14;&#xC774;&#xD2B8; hex &#xCD94;&#xCD9C; ( od &#xBA85;&#xB839;&#xC740; &#xC635;&#xC158; &#xAC12;&#xC73C;&#xB85C; 8, 16 &#xC9C4;&#xC218; &#xBAA8;&#xB450; &#xC0AC;&#xC6A9; &#xAC00;&#xB2A5; )</span>
$ <span class="hljs-built_in">echo</span> ABCDEFGHIJK | od -j2 -N4 -tx1z
<span class="hljs-number">0000002</span> <span class="hljs-number">43</span> <span class="hljs-number">44</span> <span class="hljs-number">45</span> <span class="hljs-number">46</span>                                      &gt;CDEF&lt;
<span class="hljs-number">0000006</span>

$ <span class="hljs-built_in">echo</span> ABCDEFGHIJK | hd <span class="hljs-operator">-s</span>2 -n4
<span class="hljs-number">00000002</span>  <span class="hljs-number">43</span> <span class="hljs-number">44</span> <span class="hljs-number">45</span> <span class="hljs-number">46</span>                                     |CDEF|
<span class="hljs-number">00000006</span>
</code></pre>
<p>hex &#xAC12;&#xC774; &#xC544;&#xB2CC; &#xC815;&#xC218;&#xB098; float &#xAC12;&#xC73C;&#xB85C; &#xCD9C;&#xB825;&#xD558;&#xACE0; &#xC2F6;&#xC73C;&#xBA74;
&#xA0;&#xA0;&#xA0;&#xA0;&#xA0; &#xA0;&#xA0;&#xA0;&#xA0;&#xA0;
&#xA0;&#xA0;&#xA0;&#xA0;&#xA0; &#xA0;&#xA0;&#xA0;&#xA0;&#xA0;
&#xA0;&#xA0;&#xA0;&#xA0;&#xA0; &#xA0;&#xA0;&#xA0;&#xA0;&#xA0;
&#xA0;&#xA0;&#xA0;&#xA0;&#xA0; &#xA0;&#xA0;&#xA0;&#xA0;&#xA0;
( &#xCC38;&#xC870;: <a href="https://youtu.be/BjL0hAvwpSE" target="_blank">hex &#xC5D0;&#xB514;&#xD305;</a> )</p>
<p><img src="images/here_document_ex.png" alt=""></p>
<pre><code class="lang-bash"><span class="hljs-comment"># 8 &#xBC14;&#xC774;&#xD2B8; &#xAC74;&#xB108;&#xB6F0;&#xACE0;(-j8), 8 &#xBC14;&#xC774;&#xD2B8;&#xB97C; &#xC77D;&#xC74C;(-N8), &#xAC01;&#xAC01; 4 &#xBC14;&#xC774;&#xD2B8;&#xC529;&#xC744; signed decimal &#xB85C; &#xCC98;&#xB9AC;(-td4) </span>
<span class="hljs-comment"># x86 cpu &#xB294; little endian &#xC774;&#xBBC0;&#xB85C; 03 00 00 00 &#xAC12;&#xC774; &#xC815;&#xC218;&#xAC12;&#xC73C;&#xB85C; &#xCC98;&#xB9AC;&#xB420; &#xB54C;&#xB294;</span>
<span class="hljs-comment"># &#xC791;&#xC740;&#xCABD;(little) &#xC8FC;&#xC18C;&#xC758; &#xBC14;&#xC774;&#xD2B8; &#xAC12;&#xC774; &#xC22B;&#xC790; &#xB05D;&#xC73C;&#xB85C;(endian) &#xC624;&#xAC8C; &#xB3FC;&#xC11C; 0x00000003 &#xC774; &#xB429;&#xB2C8;&#xB2E4;.</span>
$ od -j8 -N8 -td4 binary
<span class="hljs-number">0000010</span>           <span class="hljs-number">3</span>           <span class="hljs-number">4</span>
<span class="hljs-number">0000020</span>

<span class="hljs-comment"># 16 &#xBC14;&#xC774;&#xD2B8;&#xB97C; &#xC77D;&#xC5B4;&#xB4E4;&#xC774;&#xACE0;(-N16) &#xAC01;&#xAC01; 8 &#xBC14;&#xC774;&#xD2B8;&#xB97C; unsinged deciaml &#xB85C; &#xCC98;&#xB9AC;(-tu8)</span>
$ od -j16 -N16 -tu8 binary
<span class="hljs-number">0000020</span>                    <span class="hljs-number">5</span>                    <span class="hljs-number">6</span>
<span class="hljs-number">0000040</span>

<span class="hljs-comment"># 4 &#xBC14;&#xC774;&#xD2B8;&#xB97C; &#xC77D;&#xC5B4;&#xB4E4;&#xC774;&#xACE0;(-N4) &#xAC01;&#xAC01; 2 &#xBC14;&#xC774;&#xD2B8;&#xB97C; unsinged deciaml &#xB85C; &#xCC98;&#xB9AC;(-tu2)</span>
$ od -j32 -N4 -tu2 binary
<span class="hljs-number">0000040</span>      <span class="hljs-number">7</span>      <span class="hljs-number">8</span>
<span class="hljs-number">0000044</span>
</code></pre>
<h1 id="3">3.</h1>
<p>&#xD30C;&#xC77C; A &#xC758; &#xD2B9;&#xC815; &#xC704;&#xCE58;&#xC5D0;&#xC11C; &#xBC14;&#xC774;&#xD2B8;&#xB97C; &#xCD94;&#xCD9C;&#xD574;&#xC11C; &#xD30C;&#xC77C; B &#xC758; &#xD2B9;&#xC815; &#xC704;&#xCE58;&#xC5D0; &#xC4F0;&#xAE30;&#xB97C; &#xD558;&#xB824;&#xBA74; &#xC5B4;&#xB5BB;&#xAC8C; &#xD560;&#xAE4C;&#xC694;?</p>
<p>&#xC774;&#xB54C;&#xB294; <code>dd</code> &#xBA85;&#xB839;&#xACFC; <code>conv=notruc</code> &#xC635;&#xC158;&#xC744; &#xC0AC;&#xC6A9;&#xD569;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash">$ cat infile                      $ cat outfile 
<span class="hljs-number">1111111111</span>                        aaaaaaaaaaaaaaaaaaaa
<span class="hljs-number">2222222222</span>                        bbbbbbbbbbbbbbbbbbbb
<span class="hljs-number">3333333333</span>                        cccccccccccccccccccc
<span class="hljs-number">1234567890</span>                        dddddddddddddddddddd
                                  eeeeeeeeeeeeeeeeeeee

<span class="hljs-comment"># 1. infile &#xC5D0;&#xC11C; 11 * 3 bytes &#xB97C; skip &#xD55C; &#xC704;&#xCE58;&#xC5D0;&#xC11C; &#xBC14;&#xC774;&#xD2B8;&#xB97C; &#xC77D;&#xC5B4;&#xB4E4;&#xC785;&#xB2C8;&#xB2E4;.</span>
<span class="hljs-comment"># 2. outfile &#xC5D0;&#xC11C; 21 * 2 bytes &#xAC74;&#xB108;&#xB6F4;( seek ) &#xC704;&#xCE58;&#xC5D0; &#xBC14;&#xC774;&#xD2B8;&#xB97C; &#xC4F0;&#xAE30; &#xD569;&#xB2C8;&#xB2E4;.</span>
<span class="hljs-comment"># 3. &#xC77D;&#xAE30;, &#xC4F0;&#xAE30; &#xD560;&#xB54C; block size &#xB294; 1 byte &#xB85C; &#xD558;&#xACE0; 10 &#xD68C; &#xC4F0;&#xAE30; &#xD569;&#xB2C8;&#xB2E4;.</span>
<span class="hljs-comment"># 4. conv=notrunc &#xC635;&#xC158;&#xC740; &#xD30C;&#xC77C;&#xC5D0; &#xC4F0;&#xAE30;&#xB97C; &#xD560;&#xB54C; &#xD30C;&#xC77C;&#xC774; truncate &#xB418;&#xC9C0; &#xC54A;&#xAC8C; &#xD569;&#xB2C8;&#xB2E4;.</span>
$ dd <span class="hljs-keyword">if</span>=infile skip=$(( <span class="hljs-number">11</span>*<span class="hljs-number">3</span> )) of=outfile seek=$(( <span class="hljs-number">21</span>*<span class="hljs-number">2</span> )) bs=<span class="hljs-number">1</span> count=<span class="hljs-number">10</span> conv=notrunc
<span class="hljs-number">10</span>+<span class="hljs-number">0</span> records <span class="hljs-keyword">in</span>
<span class="hljs-number">10</span>+<span class="hljs-number">0</span> records out
<span class="hljs-number">10</span> bytes copied, <span class="hljs-number">0.000742817</span> s, <span class="hljs-number">13.5</span> kB/s

$ cat outfile 
aaaaaaaaaaaaaaaaaaaa
bbbbbbbbbbbbbbbbbbbb
<span class="hljs-number">1234567890</span>cccccccccc
dddddddddddddddddddd
eeeeeeeeeeeeeeeeeeee
</code></pre>
<p><code>dd</code> &#xBA85;&#xB839;&#xC740; &#xD30C;&#xC77C;&#xBFD0;&#xB9CC; &#xC544;&#xB2C8;&#xB77C; device &#xC7A5;&#xCE58; &#xD30C;&#xC77C;&#xC5D0;&#xB3C4; &#xB3D9;&#xC77C;&#xD558;&#xAC8C; &#xC801;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-bash"><span class="hljs-comment"># /dev/sda &#xB514;&#xC2A4;&#xD06C;&#xC758; MBR &#xB97C; sdambr.img &#xD30C;&#xC77C;&#xB85C; &#xBC31;&#xC5C5;</span>
$ sudo dd <span class="hljs-keyword">if</span>=/dev/sda of=sdambr.img bs=<span class="hljs-number">512</span> count=<span class="hljs-number">1</span>
<span class="hljs-comment"># sdambr.img &#xD30C;&#xC77C;&#xB85C; &#xBD80;&#xD130; MBR &#xBCF5;&#xAD6C;</span>
$ sub dd <span class="hljs-keyword">if</span>=sdambr.img of=/dev/sda

<span class="hljs-comment"># &#xB2E4;&#xC74C;&#xACFC; &#xAC19;&#xC774; &#xD558;&#xBA74; &#xBD80;&#xD305; &#xAC00;&#xB2A5;&#xD55C; &#xC6B0;&#xBD84;&#xD22C; USB &#xAC00; &#xB9CC;&#xB4E4;&#xC5B4;&#xC9D1;&#xB2C8;&#xB2E4;. ( usb &#xB294; /dev/sdb )</span>
$ sudo dd <span class="hljs-keyword">if</span>=ubuntu-desktop-amd64.iso of=/dev/sdb bs=<span class="hljs-number">1</span>M oflag=direct status=progress
</code></pre>

                    
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