showgraph.cgi is passed a QUERY_STRING environment variable with the following parameters:
host Name of the host to generate a graph for
service Name of the service to generate a graph for
disp Display-name of the host, used on the generated graphs instead of hostname.
graph Can be "hourly", "daily", "weekly" or "monthly" to select the time period that the graph covers.
first Used to split multi-graphs into multiple graphs. This causes showgraph.cgi to generate only the graphs starting with the "first'th" graph and continuing for "count".
count Number of graphs in a multi-graph.
upper Set the upper limit of the graph. See rrdgraph(1) for a description of the "-u" option.
lower Set the lower limit of the graph. See rrdgraph(1) for a description of the "-l" option.
graph_start Set the starttime of the graph. This is used in zoom-mode.
graph_end Set the end-time of the graph. This is used in zoom-mode.
action=menu Generate an HTML page with links to 4 graphs, representing the hourly, weekly, monthly and yearly graphs. Doesn't actually generate any graphs, only the HTML that links to the graphs.
action=showzoom Generate HTML with a link to the zoomed graph image. This link goes to an "action=view" invocation of showgraph.cgi.
action=view Generate a single graph image.
QUERY_STRING Provided by the webserver CGI interface, this decides what graph to generate.
RRDGRAPHOPTS RRD-specific options for the graph. This is usually set in the xymonserver.cfg(5) file.
graphs.cfg: The configuration file determining how graphs are generated from RRD files.