in reply to Another system redirect problem

As an anonymous monk explained, you can't execute a shell command (of which ">>" is a part) without running a shell!

IPC::Open3 is a somewhat low-level way of doing it, but it's an option. 

use IPC::Open3 qw( open3 );

open(local *OUT_FH, '>>', '/Volumes/Expansion Drive/stuffTGZ/list_xxx_
+dirs.txt') or die $!;

print(OUT_FH "-------------------------------------------------\n");
print(OUT_FH "- $File::Find::name -----------------------------\n");

# Gets closed by open3.
open(local *CHILD_STDIN, '<', '/dev/null') or die $!;

my $pid = open3(
   '<&CHILD_STDIN', '>&OUT_FH', '>&STDERR',
   "/bin/ls" => ( "-l", $File::Find::name ),
);

waitpid($pid, 0);

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You can reuse OUT_FH for multiple calls to open3, but you need to reopen CHILD_STDIN each time.

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Re^2: Another system redirect problem
by Anonymous Monk on Jun 18, 2011 at 06:43 UTC
    I believe IPC::Run provides a solution 
          # Can do I/O to sub refs and filenames, too:
run \@cmd, '<', "in.txt", \&out, \&err or die "cat: $?"
run \@cat, '<', "in.txt", '>>', "out.txt", '2>>', "err.txt";

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[d/l]

      From what I gathered from the docs and a lot of testing, it would look like 

      use IPC::Run qw( run );

open(my $fh, '>>', '/Volumes/Expansion Drive/stuffTGZ/list_xxx_dirs.tx
+t') or die $!;

print($fh "-------------------------------------------------\n");
print($fh "- $File::Find::name -----------------------------\n");

run
   [ "/bin/ls" => ( "-l", $File::Find::name ) ],
   '<', \"", '>', $fh;

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      Notes:

      • Lexical file handles work, but I didn't see it in the documentation.
      • «'<', \""» appears to open /dev/null (desirable) as opposed to closing STDIN as documented (undesirable).
      • The child appears to inherit the parent's STDERR if 2> isn't specified. That's probably documented, but I didn't see it.
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