my $a = '\[a\]';
my $b = '\[b\]';

open(HANDLE, "$dataFile") or warn "Error: Unable to open data file";

my @raw_data=<HANDLE>;

foreach my $line (@raw_data) {

	if ($line =~ /$a/ )  {
	    # Process
	}
	if ($line =~ /$b/) {
	    # Process 
	}
	
}
close HANDLE;