There are modules that will determine file type for you, however if you just want to check for a text file you can probably just use this heuristic:

my $file = 'C:/tmp.zip';
open F, $file or die $!; 
read( F, my $buf, 1024 );
close F;
print is_text($buf) ? "$file is TEXT\n" : "$file is BIN\n";

# alternatively you can just...
print -T $file ? "-T $file is TEXT\n" : "-T $file is BIN\n";

sub is_text {
    my ($data) = @_;
  return 0 unless $data;
  return 0 if $data =~ m![\x00-\x08\x0b\x0e-\x1f]!;
  return 1;
}
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All it does is look for any chars that should not be in a TEXT file but are found in binary files. The 1024 char is arbitrary but is the one used by file. There is also the -T file test in Perl which does something similar but needs a real file or handle rather than just a data buffer...

cheers

tachyon

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