use YAML qw( DumpFile );

my @data = (
    [
        {
            "title" => "line 1", 
            "style" => "lines" , 
            "type" => "matrix"
        }, 
        [ 1, 6318 ], 
        [ 2, 7903 ], 
        [ 3, 25617 ], 
    ],
    [
        { 
            "title" => "line 2", 
            "style" => "lines" , 
            "type" => "matrix"
        }, 
        [ 1, 6215 ], 
        [ 2, 7831 ], 
        [ 3, 25782 ],
    ],
);

DumpFile( "output.txt", @data )

##</code><code>##

--- #YAML:1.0
- style: lines
  title: line 1
  type: matrix
-
  - 1
  - 6318
-
  - 2
  - 7903
-
  - 3
  - 25617
--- #YAML:1.0
- style: lines
  title: line 2
  type: matrix
-
  - 1
  - 6215
-
  - 2
  - 7831
-
  - 3
  - 25782

##</code><code>##

use YAML qw( LoadFile );

my @data = LoadFile( "output.txt" );

gnuplot({ "title" => "My Trend",
          "output type" => "png",
          "output file" => "$TMPDIR/trend-$$.png"},
           @data
       );