parsing cgi lua

#!/usr/bin/env lua

print ("Content-type: Text/html\n")

local info = os.getenv("QUERY_STRING")
local params = {}
local echo = {}

pagetop = [[
<html>
<head>

<body text=blue>

<form>
user:<br><input name=user><br>
pass:<br><input name=pass><br>
<input type=submit value="go!">

</form>
Result:
]]

pagebase = [[
<br><br>
</body>
</html>
]]


for name, value in string.gmatch(info .. '&', '(.-)%=(.-)%&') do
        value = string.gsub(value , '%+', ' ')
        value = string.gsub(value , '%%(%x%x)', function(dpc)
                return string.char(tonumber(dpc,16))
                end )
        params[name] = value

        value = string.gsub(value, "%&", "&amp;")
        value = string.gsub(value, "%<", "&lt;")
        value = string.gsub(value, '%"', "&quot;")
        echo[name] = value

        end

print (pagetop)

if params["user"] == "test" then
    user= params["user"]
    pass= params["pass"]
    cmd = io.popen("/var/www/cgi-bin/./test.sh '"..user.." "..pass.."'")
    output = cmd:read('*all')
    cmd:close()
    print(output)
end

print (pagebase)