[ns] problem with awk script

[Giuseppe Tringali <gtringali@katamail.com>]

Hi all,

I have tried to execute, for the first time, an awk script.
This script has been provided by:

<L.Wood@surrey.ac.uk>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>

in this mailing list.

You can read the whole message at the following link:

http://www.isi.edu/nsnam/archive/ns-users/webarch/1999/msg02093.html

Or you can read only the script below:

BEGIN {
    # simple awk script to generate end-to-end packet lifetime statistics
    # in a form suitable for plotting with xgraph.
    # Lloyd Wood, July 1999.
    # http://www.ee.surrey.ac.uk/Personal/L.Wood/ns/

    highest_packet_id = 0;
}

{
    action = $1;
    time = $2;
    node_1 = $3;
    node_2 = $4;
    src = $5;
    flow_id = $8;
    node_1_address = $9;
    node_2_address = $10;
    seq_no = $11;
    packet_id = $12;


    if ( packet_id > highest_packet_id ) highest_packet_id = packet_id;

    # getting start time is not a problem, provided you're not starting
    # traffic at 0.0.
    # could test for sending node_1_address or flow_id here.
    if ( start_time[packet_id] == 0 )  start_time[packet_id] = time;

    # only useful for small unicast where packet_id doesn't wrap.
    # checking receive means avoiding recording drops
    if ( action != "d" ) {
       if ( action == "r" ) {
         # could test for receiving node_2_address or flow_id here.
          end_time[packet_id] = time;
       }
    } else {
       end_time[packet_id] = -1;
    }
}
END {
     for ( packet_id = 0; packet_id <= highest_packet_id; packet_id++ ) {
        start = start_time[packet_id];
        end = end_time[packet_id];
        packet_duration = end - start;

        if ( start < end ) printf("%d %f\n", start, packet_duration);
    }
}


I've saved it as end-to-end.awk. At the prompt I have typed:

awk -f end-to-end.awk out.tr > end.tr

I get this error message:

awk: end-to-end.awk:1: BEGIN {
' in expression.awk:1:        ^ Invalid char '


Where is my mistake?

Linux distribution: Red Hat 6.2

Any help is appreciated, thank you.