use strict;
use Fcntl ':flock';

my $iniFile = 'config.ini';
if (open my $ini, "+<$iniFile"){
  if (flock $ini, LOCK_EX){
    my @data = <$ini>;
    # Work with @data -- delete lines, update lines, etc.
    if (truncate($ini, 0) and seek($ini, 0, 0)){
      print "Can't write to $iniFile : $!\n"
                        unless print $ini @data;
    }else{
      print "Can't truncate/seek : $!\n";
    }
  }else{
    print "Can't lock : $!\n";
  }
  close $ini;
}else{
  print "Can't open $iniFile : $!\n";
}