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<h4 class="subsection">1.2.2 Parameter Mode</h4>

<p><a name="index-parameter-mode-24"></a>In parameter mode, the argument to the function given by the virtual
code is a data structure containing environment variables and command
line parameters including files, application specific options, and
possibly standard input. The result obtained by evaluating the
function is either a data structure representing a set of files to be
written, which may include standard output, or a sequence of shell
commands to be executed, or a combination of both. Parameter mode is
indicated whenever either of these conditions is met.

     <ul>
<li>Any of the parameter mode options appears on the
command line preceding the first filename parameter. 
See <a href="Parameter-Mode-Options.html#Parameter-Mode-Options">Parameter Mode Options</a>. 
<li>At least one additional filename parameter or option follows the first
filename parameter, and the option <samp><span class="option">--unparameterized</span></samp> does not
precede it. 
</ul>

<p class="noindent">Examples:

     <dl>
<dt><kbd>avram --map-to-each-file prettyprinter.avm *.c *.h --extra-pretty</kbd><dd>In this example, parameter mode is indicated both by the parameter
mode option <samp><span class="option">--map-to-each-file</span></samp> and by the presence of input
file names and the <samp><span class="option">--extra-pretty</span></samp> option. The latter is
specific to the hypothetical <code>prettyprinter.avm</code> virtual code
application, as indicated by its position on the command line, and is
therefore passed to it by <code>avram</code>. 
<br><dt><kbd>cat ~/specfile | avram reportgenerator -v - /var/log/syslog</kbd><dd>In this example, a hypothetical parameter mode application
<code>reportgenerator</code> is able to read <samp><span class="file">~/specfile</span></samp> from standard
input because of the <code>-</code> used as a parameter. 
<br><dt><kbd>avram --parameterized grepenv</kbd><dd>In this example, a hypothetical application that searches shell
variables is invoked in parameter mode even with no input files or
application specific options, because of the  <samp><span class="option">--parameterized</span></samp>
option. Parameter mode invocation is required by the application to give
it access to the environment. 
<br><dt><kbd>avram grepenv --search-targets=PATH,MANPATH</kbd><dd>This example shows an application specific option with both a keyword
and a parameter list. They suffice to indicate parameter mode without
an explicit <samp><span class="option">--parameterized</span></samp> option. 
</dl>

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