open(DPSLOTFILE, "< c:\\test.txt") or die "Can't open file: $!";

while ( <DPSLOTFILE> ) {
   my $buffer .= $_;
}

$buffer =~ s/\[|\]//g;
close DPSLOTFILE;

open(NEWFILE, ">+C:\\output.txt");
print NEWFILE $buffer;
close(NEWFILE);