| 1 | <html><head><title>CGI Command line options</title></head><body><h1><img alt="" src="cl_files/CGIlogo.gif"> CGI Command line options</h1>
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| 2 | <hr> <p>
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| 3 |
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| 4 | </p><h2>Specification</h2>
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| 5 |
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| 6 | The command line is only used in the case of an ISINDEX query. It is
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| 7 | not used in the case of an HTML form or any as yet undefined query
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| 8 | type. The server should search the query information (the <code>QUERY_STRING</code> environment variable) for a non-encoded
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| 9 | = character to determine if the command line is to be used, if it
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| 10 | finds one, the command line is not to be used. This trusts the clients
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| 11 | to encode the = sign in ISINDEX queries, a practice which was
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| 12 | considered safe at the time of the design of this specification. <p>
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| 13 |
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| 14 | For example, use the <a href="http://hoohoo.ncsa.uiuc.edu/cgi-bin/finger">finger script</a> and the ISINDEX interface to look up "httpd". You will see that the script will call itself with <code>/cgi-bin/finger?httpd</code> and will actually execute "finger httpd" on the command line and output the results to you.
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| 15 | </p><p>
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| 16 | If the server does find a "=" in the <code>QUERY_STRING</code>,
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| 17 | then the command line will not be used, and no decoding will be
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| 18 | performed. The query then remains intact for processing by an
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| 19 | appropriate FORM submission decoder.
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| 20 | Again, as an example, use <a href="http://hoohoo.ncsa.uiuc.edu/cgi-bin/finger?httpd=name">this hyperlink</a> to submit <code>"httpd=name"</code> to the finger script. Since this <code>QUERY_STRING</code>
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| 21 | contained an unencoded "=", nothing was decoded, the script didn't know
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| 22 | it was being submitted a valid query, and just gave you the default
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| 23 | finger form.
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| 24 | </p><p>
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| 25 | If the server finds that it cannot send the string due to internal
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| 26 | limitations (such as exec() or /bin/sh command line restrictions) the
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| 27 | server should include NO command line information and provide the
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| 28 | non-decoded query information in the environment
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| 29 | variable <a href="http://hoohoo.ncsa.uiuc.edu/cgi/env.html#query"><code>QUERY_STRING</code></a>. </p><p>
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| 30 | </p><hr>
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| 31 | <h2>Examples</h2>
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| 32 |
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| 33 | Examples of the command line usage are much better <a href="http://hoohoo.ncsa.uiuc.edu/cgi/examples.html">demonstrated</a> than explained. For these
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| 34 | examples, pay close attention to the script output which says what
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| 35 | argc and argv are. <p>
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| 36 |
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| 37 | </p><hr>
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| 38 |
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| 39 | <a href="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html"><img alt="[Back]" src="cl_files/back.gif">Return to the
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| 40 | interface specification</a> <p>
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| 41 |
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| 42 | CGI - Common Gateway Interface
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| 43 | </p><address><a href="http://hoohoo.ncsa.uiuc.edu/cgi/mailtocgi.html">cgi@ncsa.uiuc.edu</a></address>
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| 44 |
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| 45 |
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| 46 | </body></html>
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