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Top Forums UNIX for Advanced & Expert Users [BASH] Read pipe of unkown number of arguments? Post 302945802 by Don Cragun on Wednesday 3rd of June 2015 04:08:06 AM
Old 06-03-2015
Quote:
Originally Posted by sea
... ... ...

Now i tried to remove the array, and shorten it a bit, now it behaves weird.
Code:
[ -z "$1" ] && \
	while read  ARG
	do	set "$ARG"
	done
for item in "${@}"
do	echo "something with $item"
done

Code:
0 ~/tmp $ ./get-pipe.sh *
something with browser
something with get-pipe.sh
something with get-pipe-test.sh
something with test with spaces

0 ~/tmp $  ls | ./get-pipe.sh 
something with test with spaces

0 ~/tmp $

Even with while IFS="$IFS\l" read ARG there was no difference.
Any ideas please?

(edit: Or should i better stay with the array?)
Not weird at all. Every time through the read loop, set clears all of the arguments you have accumulated. Try something more like:
Code:
if [ $# -eq 0 ]
then	while IFS= read -r ARG
	do	set -- "$@" "$ARG"
	done
fi
printf 'Arg count: %d\n' $#
printf '\targ: "%s"\n' "$@"

But, this still won't work if you have an argument that has embedded <newline> characters.
This User Gave Thanks to Don Cragun For This Post:
 

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PIPE(2) 							System Calls Manual							   PIPE(2)

NAME
pipe - create an interprocess channel SYNOPSIS
pipe(fildes) int fildes[2]; DESCRIPTION
The pipe system call creates an I/O mechanism called a pipe. The file descriptors returned can be used in read and write operations. When the pipe is written using the descriptor fildes[1] up to 4096 bytes of data are buffered before the writing process is suspended. A read using the descriptor fildes[0] will pick up the data. Writes with a count of 4096 bytes or less are atomic; no other process can inter- sperse data. It is assumed that after the pipe has been set up, two (or more) cooperating processes (created by subsequent fork calls) will pass data through the pipe with read and write calls. The Shell has a syntax to set up a linear array of processes connected by pipes. Read calls on an empty pipe (no buffered data) with only one end (all write file descriptors closed) returns an end-of-file. SEE ALSO
sh(1), read(2), write(2), fork(2) DIAGNOSTICS
The function value zero is returned if the pipe was created; -1 if too many files are already open. A signal is generated if a write on a pipe with only one end is attempted. BUGS
Should more than 4096 bytes be necessary in any pipe among a loop of processes, deadlock will occur. ASSEMBLER
(pipe = 42.) sys pipe (read file descriptor in r0) (write file descriptor in r1) PIPE(2)
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