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     <h4 class="title">
      <a name="option-modifiers">
      </a>
      6.2.2.4 Program Option Modifiers
     </h4>
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  <p>
   Some options are
   <span class="quote">
    “
    <span class="quote">
     boolean
    </span>
    ”
   </span>
   and control behavior
        that can be turned on or off. For example, the
   <a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
    <span class="command">
     <strong>
      mysql
     </strong>
    </span>
   </a>
   client supports a
   <a class="link" href="mysql-command-options.html#option_mysql_column-names">
    <code class="option">
     --column-names
    </code>
   </a>
   option that
        determines whether or not to display a row of column names at
        the beginning of query results. By default, this option is
        enabled. However, you may want to disable it in some instances,
        such as when sending the output of
   <a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
    <span class="command">
     <strong>
      mysql
     </strong>
    </span>
   </a>
   into
        another program that expects to see only data and not an initial
        header line.
  </p>
  <p>
   To disable column names, you can specify the option using any of
        these forms:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa16024440"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token property">--disable-column-names</span>
<span class="token property">--skip-column-names</span>
<span class="token constant">--column-names</span><span class="token attr-value"><span class="token punctuation">=</span>0</span></code></pre>
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  <p>
   The
   <code class="option">
    --disable
   </code>
   and
   <code class="option">
    --skip
   </code>
   prefixes and the
   <code class="literal">
    =0
   </code>
   suffix all have the same
        effect: They turn the option off.
  </p>
  <p>
   The
   <span class="quote">
    “
    <span class="quote">
     enabled
    </span>
    ”
   </span>
   form of the option may be specified
        in any of these ways:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa53023318"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token property">--column-names</span>
<span class="token property">--enable-column-names</span>
<span class="token constant">--column-names</span><span class="token attr-value"><span class="token punctuation">=</span>1</span></code></pre>
  </div>
  <p>
   The values
   <code class="literal">
    ON
   </code>
   ,
   <code class="literal">
    TRUE
   </code>
   ,
   <code class="literal">
    OFF
   </code>
   , and
   <code class="literal">
    FALSE
   </code>
   are also
        recognized for boolean options (not case-sensitive).
  </p>
  <p>
   If an option is prefixed by
   <code class="option">
    --loose
   </code>
   , a program
        does not exit with an error if it does not recognize the option,
        but instead issues only a warning:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa81748170"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$&gt; </span><span class="token command">mysql</span> <span class="token property">--loose-no-such-option</span>
mysql<span class="token punctuation">:</span> WARNING<span class="token punctuation">:</span> unknown option <span class="token atrule">'--loose-no-such-option'</span></code></pre>
  </div>
  <p>
   The
   <code class="option">
    --loose
   </code>
   prefix can be useful when you run
        programs from multiple installations of MySQL on the same
        machine and list options in an option file. An option that may
        not be recognized by all versions of a program can be given
        using the
   <code class="option">
    --loose
   </code>
   prefix (or
   <code class="literal">
    loose
   </code>
   in an option file). Versions of the
        program that recognize the option process it normally, and
        versions that do not recognize it issue a warning and ignore it.
  </p>
  <p>
   The
   <code class="option">
    --maximum
   </code>
   prefix is available for
   <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
    <span class="command">
     <strong>
      mysqld
     </strong>
    </span>
   </a>
   only and permits a limit to be placed
        on how large client programs can set session system variables.
        To do this, use a
   <code class="option">
    --maximum
   </code>
   prefix with the
        variable name. For example,
   <code class="option">
    --maximum-max_heap_table_size=32M
   </code>
   prevents any
        client from making the heap table size limit larger than 32M.
  </p>
  <p>
   The
   <code class="option">
    --maximum
   </code>
   prefix is intended for use with
        system variables that have a session value. If applied to a
        system variable that has only a global value, an error occurs.
        For example, with
   <code class="option">
    --maximum-back_log=200
   </code>
   , the
        server produces this error:
  </p>
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   <pre class="programlisting one-line language-none"><div class="docs-select-all right" id="sa42119828"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">Maximum value of 'back_log' cannot be set</code></pre>
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