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 - <a name="Input_002fOutput"></a>
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 - <a name="Your-Program_0027s-Input-and-Output"></a>
 - <h3 class="section">4.6 Your Program’s Input and Output</h3>
 - 
 - <a name="index-redirection"></a>
 - <a name="index-i_002fo"></a>
 - <a name="index-terminal"></a>
 - <p>By default, the program you run under <small>GDB</small> does input and output to
 - the same terminal that <small>GDB</small> uses.  <small>GDB</small> switches the terminal
 - to its own terminal modes to interact with you, but it records the terminal
 - modes your program was using and switches back to them when you continue
 - running your program.
 - </p>
 - <dl compact="compact">
 - <dd><a name="index-info-terminal"></a>
 - </dd>
 - <dt><code>info terminal</code></dt>
 - <dd><p>Displays information recorded by <small>GDB</small> about the terminal modes your
 - program is using.
 - </p></dd>
 - </dl>
 - 
 - <p>You can redirect your program’s input and/or output using shell
 - redirection with the <code>run</code> command.  For example,
 - </p>
 - <div class="smallexample">
 - <pre class="smallexample">run > outfile
 - </pre></div>
 - 
 - <p>starts your program, diverting its output to the file <samp>outfile</samp>.
 - </p>
 - <a name="index-tty"></a>
 - <a name="index-controlling-terminal"></a>
 - <p>Another way to specify where your program should do input and output is
 - with the <code>tty</code> command.  This command accepts a file name as
 - argument, and causes this file to be the default for future <code>run</code>
 - commands.  It also resets the controlling terminal for the child
 - process, for future <code>run</code> commands.  For example,
 - </p>
 - <div class="smallexample">
 - <pre class="smallexample">tty /dev/ttyb
 - </pre></div>
 - 
 - <p>directs that processes started with subsequent <code>run</code> commands
 - default to do input and output on the terminal <samp>/dev/ttyb</samp> and have
 - that as their controlling terminal.
 - </p>
 - <p>An explicit redirection in <code>run</code> overrides the <code>tty</code> command’s
 - effect on the input/output device, but not its effect on the controlling
 - terminal.
 - </p>
 - <p>When you use the <code>tty</code> command or redirect input in the <code>run</code>
 - command, only the input <em>for your program</em> is affected.  The input
 - for <small>GDB</small> still comes from your terminal.  <code>tty</code> is an alias
 - for <code>set inferior-tty</code>.
 - </p>
 - <a name="index-inferior-tty"></a>
 - <a name="index-set-inferior-controlling-terminal"></a>
 - <p>You can use the <code>show inferior-tty</code> command to tell <small>GDB</small> to
 - display the name of the terminal that will be used for future runs of your
 - program.
 - </p>
 - <dl compact="compact">
 - <dt><code>set inferior-tty [ <var>tty</var> ]</code></dt>
 - <dd><a name="index-set-inferior_002dtty"></a>
 - <p>Set the tty for the program being debugged to <var>tty</var>.  Omitting <var>tty</var>
 - restores the default behavior, which is to use the same terminal as
 - <small>GDB</small>.
 - </p>
 - </dd>
 - <dt><code>show inferior-tty</code></dt>
 - <dd><a name="index-show-inferior_002dtty"></a>
 - <p>Show the current tty for the program being debugged.
 - </p></dd>
 - </dl>
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