I looked for that the "-" modifier does in front of pipe symbol,

It's the 3-arg form of "command|" 

open(my $pipe, "$command |")    # 2-arg form
open(my $pipe, '-|', $command)  # 3-arg form

[download]

"open()" does NOT return a PID

Actually, it does when using open to create a process and pipe. This is documented.

And it appears that -| and |- without further arguments simply forks without executing anything instead of giving an error or trying to launch a program named "-". This doesn't seem to be documented. [ Apparently it is, just not in open. See reply ]

In reply to Re^2: Issue with communication of large data between Parent and child using Perl pipes by ikegami
in thread Issue with communication of large data between Parent and child using Perl pipes by waavman

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