See Brief request syntax to understand each keyword.

 #!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
  
server = ECMWFDataServer()
  
server.retrieve({
    'dataset' : "tigge",
    'step'    : "24/to/120/by/24",
    'number'  : "all",
    'levtype' : "sl",
    'date'    : "20071001/to/20071003",
    'time'    : "00/12",
    'origin'  : "all",
    'type'    : "pf",
    'param'   : "tp",
    'area'    : "70/-130/30/-60",
    'grid'    : "2/2",
    'target'  : "data.grib"
    })

import org.ecmwf.DataServer;
import org.json.JSONObject;
 
public class DataServerExample {
    public static void main(String[] args) throws Exception 
    {
 
        DataServer server = new DataServer(); 
 
        JSONObject  request = new JSONObject();
         
        request.put("dataset" , "tigge");
        request.put("step"    , "24/to/120/by/24");
        request.put("number"  , "all");
        request.put("levtype" , "sl");
        request.put("date"    , "20071001/to/20071003");
        request.put("time"    , "00/12");
        request.put("origin"  , "all");
        request.put("type"    , "pf");
        request.put("param"   , "tp");
        request.put("area"    , "70/-130/30/-60");
        request.put("grid"    , "2/2");
        request.put("target"  , "data.grib");
 
        server.retrieve(request);
    }
}

#!/usr/bin/env perl
use ECMWF::DataServer;
 
my $server = ECMWF::DataServer->new();
 
$server.retrieve({
    'dataset' : "tigge",
    'step'    : "24/to/120/by/24",
    'number'  : "all",
    'levtype' : "sl",
    'date'    : "20071001/to/20071003",
    'time'    : "00/12",
    'origin'  : "all",
    'type'    : "pf",
    'param'   : "tp",
    'area'    : "70/-130/30/-60",
    'grid'    : "2/2",
    'target'  : "data.grib"
    })