- unless (-d $srcdir && -d $destdir ) {die "Error: $!";}
+ for($srcdir,$destdir) { ! -d $_ and die "Directory '$_' - $!\n" }
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You wouldn't know which directory is missing.

- chdir $srcdir;
- opendir(INDIR,$srcdir) || die "Can't open directory: $!";
+ chdir $srcdir or die "Can't chdir to '$srcdir': $!\n";
+ open my $indir, '.' or die "Can't read '.' in $srcdir: $!\n";
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Point is, you are already in $srcdir, so you are here->.

Instead of using the ugly and hard to grok

unless (-d || $_ eq "." || $_ eq "..") { # . and .. are always -d
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in the loop, after having lumped all directory entries (files, directories, symlinks, sockets, device files) into @files (are you really looking for files only? and making tar.gz's containing a single file each?) it would be more elegant

my @files = grep { -f } readdir $indir;
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to stuff only the interesting files into @files.

    `tar -cz $_ -f $_.tar.gz`;
    `mv *.gz $destdir`;
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Really? what if your directory contains *.gz files? Your asking tar to complain. And use system, not backticks.

I would pack all files into one tar file:

chdir $srcdir or die "Can't chdir to '$srcdir': $!\n";
open my $indir, '.' or die "Can't read '.' in $srcdir: $!\n";

(my $tarfile = $srcdir) =~ s|.*/||;
$tarfile = "$destdir/$tarfile-" . time . '.tar';

my @files = grep { -f and -M <= 1 } readdir $indir;

# packing all files at once doesn't work with large directories
# (limit of command line length)

while(my $file = shift @files) {
    system ('tar', 'uf', $tarfile, $file)
        and die "Can't pack '$file' into '$tarfile' (exitcode $?)\n"; 
}

system ('gzip', $tarfile)
    and die "Couldn't gzip $tarfile (exitcode $?)\n";
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--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}