#!/usr1/local/bin/perl

###########################################################################
#        Change the Coordinate system
#
#        v.0.1: 08/15/07 K. Hamaguchi
#        v.0.2: 08/17/07 K. Hamaguchi, Put 0.0 on TCRVL10 and TCRVL11
#
###########################################################################

if($ARGV[0] eq "-h"){
    print "This script puts 0.0 on the sky coordinate reference keywords (TCRVL10, TCRVL11) of event files in the current directory. The event file name has to be ae*.evt. You have to uncompress the event files before running this script.\n";
    print "  Usage: chcoord.pl\n";
    die   "If you have the file \"evtlist.txt\" in the current directory, you have to remove it.\n";
}

$X_REF = 0.0;
$Y_REF = 0.0;
$EVENTFILELIST = "evtlist.txt";

if (-e $EVENTFILELIST){
  die "File \"$EVENTFILELIST\" exists.\n";
}

shellcom("ls ae*.evt > $EVENTFILELIST");

open(YOME, "<$EVENTFILELIST") || die "$EVENTFILELIST was not created";

while (<YOME>){
    chomp;
    $EVTFILE = "$_"."[1]";
    shellcom("fparkey $X_REF $EVTFILE TCRVL10");
    shellcom("fparkey $Y_REF $EVTFILE TCRVL11");
}

unlink($EVENTFILELIST) || warn "having trouble deleting $EVENTFILELIST.\n";

sub shellcom {

  print "$_[0]\n";
  system("$_[0]");

}