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<title>ploticus: controlling ploticus from other programs (automation)</title>
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  <td><br><h2>controlling ploticus from other programs (automation)</h2></td>
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.TH controlling_ploticus_from_other_programs_(automation) PL "23-AUG-2001   PL www.sgpr.net"

.SH DESCRIPTION
Notes on executing ploticus under the control of another program
in an automated way.

.SH STRATEGY
.LP
As of version 2.00, pl can be
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\0directly invoked as a CGI program
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.LP
A 
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<a href="../download/ploticus.perl">
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perl script 
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which implements a web interface to ploticus was
contributed by Tom McClure.
.LP
Since it is a command-line program, 
\fBploticus\fR can easily be invoked by other programs
automatically for unattended use.
For instance, web server CGI scripts can invoke \fBpl\fR
to build PNG or GIF data displays on demand.  Or, \fBcron\fR
could invoke \fBpltab\fR to generate and print tables at
specified times.
.LP
The invoking program can build a ploticus script on the fly,
or use one that has been created in advance.
.LP
The actual invocation can be done using the equivalent of
\fCsystem()\fR.  For example, in C:
.IP
\fCsystem( "pl -gif myfile.p ITEM=hgxz" );\fR


.SH VARIABLES
Variables may be useful for implementation of 
changeable paramters (the invoking program
would execute \fBpl\fR or \fBpltab\fR, and set variables
on the command line).
For example: 
.LP
\fCpl -gif status.p STARTDATE=010198 ENDDATE=062699 GROUP=hgc\fR

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