A couple of possibilities occur to me. First, depending on you anout of ram you have and the other processes running, reading whole files in may consume enough RAM to start swapping, which will really slow things down. So it may be best to process one file at a time and read line by line, constructing your array as you go along, rather than splicing the whole array representing your file.

Second, the first regexp could be written as

next unless $curline =~ /([05])\s*$/;
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eliminating a reverse operation on each line.

-Mark