EXPORT - retain variables across invocations

SYNOPSIS

<EXPORT $var [$var ...] [flags]>

DESCRIPTION
The EXPORT directive marks the given variables for "export" to the next invocation of the script. Their values will be retrieved the next time the script is run.

EXPORTed variables are saved when the special variable $url is printed, whose value is the URL to re-invoke the script (see here). Variables EXPORTed with the QUERY flag are saved to $urlq, whose value is a URL-encoded query string (starting with a "?" if non-empty) containing the QUERY variables.

When a user then clicks the $url link, not only is the script invoked as usual, but all variables EXPORTed at the time the $url was printed, are restored in the new invocation. Thus the script can remember a user's query, login id, etc. across multiple runs.