Perl で Post のデータを処理するサンプルです。
index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta http-equiv="Pragma" content="no-cache" />
<meta http-equiv="Cache-Control" content="no-cache" />
<meta http-equiv="CONTENT-TYPE" content="text/html; charset=utf-8" />
<title>Form</title>
</head>
<body>
<FORM method="POST" action="./test_perl.pl">
<TABLE>
<TBODY>
<TR>
<TD>数量 :</TD>
<TD><INPUT type="text" name="apple" size="3" value="1"></TD>
<TD>個</TD>
<TD>
<button>カゴに入れます</button>
</TD>
</TR>
</TBODY>
</TABLE>
</FORM>
<hr />
Jul/10/2020<br />
</body>
</html>
test_perl.pl
# ! /usr/bin/perl
#
# test_perl.pl
#
# Jul/10/2020
#
use strict;
use warnings;
use CGI;
#
print "Content-type: text/html\n\n";
print "<html>\n";
print "<head>\n";
print "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\">\n";
print "<title>CGI テスト</title>\n";
print "</head>\n";
print "<body>\n";
print "CGI テスト<p />\n";
#
my $q = new CGI;
for my $param_name ($q->param) {
print $param_name . ' = ' . $q->param($param_name) . '<p />';
}
#
print "<p />\n";
print "Jul/10/2020<p />\n";
print "</body>\n";
print "</html>\n";