Shell Programming and Scripting

function YMDtoMJD (year, month, day)
{    

    var year;
    var monthi
    var day;
    var yr  = Math.floor (year); 
    var mn  = Math.floor (month);
    var day = Math.floor (day);          
    var hr  = 0.0;                    // Hours are not valid
    var L;
    var julian;    
    var mjd;
        
        
    // In leap years, -1 for Jan, Feb, else 0
    L = Math.ceil ((mn - 14) / 12);
             
    var p1 = day - 32075 + Math.floor (1461 * (yr + 4800 + L) / 4);
    
    var p2 = Math.floor (367 * (mn - 2 - L * 12) / 12);
    var p3 = 3 * Math.floor (Math.floor ((yr + 4900 + L) / 100) / 4);
    
    julian = p1 + p2 - p3;        
    julian = julian + (hr / 24.0) - 0.5;
  
    mjd = julian - 2400000.5;
    
    
    return (mjd);

}

$ echo $(($(date "+%s" -d 20041223)/86400+40588))
53362