opendir THISDIR, 'whatever/thisdir';
my @files = readdir(THISDIR);
foreach my $x (@FILES){

open READFILE, "whatever/thisdir/$x";
open WRITEFILE, ">whatever/thatdir/$x";

while(<READFILE>){
chomp;
my @parts = split(/\s/, $_);
print WRITEFILE $parts[1], " ", $parts[0], "\n";
}
close WRITEFILE;
close READFILE;
}
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