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Top Forums UNIX for Advanced & Expert Users [BASH] Read pipe of unkown number of arguments? Post 302945791 by Don Cragun on Tuesday 2nd of June 2015 11:03:35 PM
Old 06-03-2015
In cases like this, echo is your enemy. The shell removes the quotes as it processes arguments it passes to echo and when read sees the echo output on the other side of the pipe, it can't determine which blanks are supposed to be argument separators and which are supposed to be data in an argument.

If you are trying to maintain variable boundaries in arguments passed to a shell, passing those arguments as command-line arguments will always be easier than trying to reconstruct argument boundaries read through a pipeline.

If you must pass parameters though a pipeline, you have to choose a character (or string) that can never appear in any string to want to treat as a variable as your field separator instead of using the default IFS=<space><tab><newline> as field separators.
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IO::Pipe(3pm)						 Perl Programmers Reference Guide					     IO::Pipe(3pm)

NAME
IO::Pipe - supply object methods for pipes SYNOPSIS
use IO::Pipe; $pipe = IO::Pipe->new(); if($pid = fork()) { # Parent $pipe->reader(); while(<$pipe>) { ... } } elsif(defined $pid) { # Child $pipe->writer(); print $pipe ... } or $pipe = IO::Pipe->new(); $pipe->reader(qw(ls -l)); while(<$pipe>) { ... } DESCRIPTION
"IO::Pipe" provides an interface to creating pipes between processes. CONSTRUCTOR
new ( [READER, WRITER] ) Creates an "IO::Pipe", which is a reference to a newly created symbol (see the "Symbol" package). "IO::Pipe::new" optionally takes two arguments, which should be objects blessed into "IO::Handle", or a subclass thereof. These two objects will be used for the system call to "pipe". If no arguments are given then method "handles" is called on the new "IO::Pipe" object. These two handles are held in the array part of the GLOB until either "reader" or "writer" is called. METHODS
reader ([ARGS]) The object is re-blessed into a sub-class of "IO::Handle", and becomes a handle at the reading end of the pipe. If "ARGS" are given then "fork" is called and "ARGS" are passed to exec. writer ([ARGS]) The object is re-blessed into a sub-class of "IO::Handle", and becomes a handle at the writing end of the pipe. If "ARGS" are given then "fork" is called and "ARGS" are passed to exec. handles () This method is called during construction by "IO::Pipe::new" on the newly created "IO::Pipe" object. It returns an array of two objects blessed into "IO::Pipe::End", or a subclass thereof. SEE ALSO
IO::Handle AUTHOR
Graham Barr. Currently maintained by the Perl Porters. Please report all bugs to <perlbug@perl.org>. COPYRIGHT
Copyright (c) 1996-8 Graham Barr <gbarr@pobox.com>. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.18.2 2013-11-04 IO::Pipe(3pm)
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