As already suggested by vinoth.ree, but somewhat buried in a longer post, I would recommend using the glob which makes things easier that the opendir/readdir combination for 2 reasons: glob does not return the . and .. special entries (wgich you don't want to process) and returns files with their path. So you could simply write: 
my $dir = "/temp/";
for my $file (glob "$dir/*") {
    next unless -f $file; # process only regular files, not dirs
    open (my $F, $file) or die "cannot open file $!";
    while (<$F>){
        print $_;
    }
    close $F;
}
# closedir(DIR); -- not needed with glob

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I made a few additional changes reflecting the currently widely accepted good practices.

In reply to Re: File handling basics by Laurent_R
in thread File handling basics by ElectroRed

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