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Full Discussion: How to export a variable from a subshell to the parent shell?
Top Forums Shell Programming and Scripting How to export a variable from a subshell to the parent shell? Post 302612495 by Scrutinizer on Monday 26th of March 2012 05:44:41 AM
Old 03-26-2012
I would use mkfifo instead of mknod. You do not need the ( ) in this case.. If you have more than one write statement, it is better to use exec, otherwise VARIABLE=`cat $TMPFIFO` goes on after the first command writes an EOF and the sub process will not finish.
Code:
FIFO="/tmp/fifo.$$"
if ! [ -p "$FIFO" ]; then
  mkfifo "$FIFO"
fi
{ exec >"$FIFO"; sleep 2; ps -f ;echo "hello from $FIFO" ;} &
var=$(< "$FIFO")
rm "$FIFO"
echo "$var"

In ksh93 you can use coprocesses:
Code:
#!/bin/ksh
{ sleep 2; ps -f ;echo "hello from coproc" ;} |&
var=$(<&p)
echo "$var"

---------- Post updated at 11:44 ---------- Previous update was at 10:45 ----------

bash 4:
Code:
#!/bin/bash
coproc TEST { sleep 2; ps -f ;echo "hello from coproc" ;}
var=$(cat <&${TEST[0]})
echo "$var"

Last edited by Scrutinizer; 03-26-2012 at 05:56 AM..
This User Gave Thanks to Scrutinizer For This Post:
vomv1988
 

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LEARN ABOUT OPENSOLARIS

shells

shells(4)							   File Formats 							 shells(4)

NAME

       shells - shell database

SYNOPSIS

       /etc/shells

DESCRIPTION

       The shells file contains a list of the shells on the system. Applications use this file to determine whether a shell is valid. See getuser-
       shell(3C). For each shell a single line should be present, consisting of the shell's path, relative to root.

       A hash mark (#) indicates the beginning of a comment; subsequent characters up to the end of the line are not interpreted by  the  routines
       which search the file. Blank lines are also ignored.

       The following default shells are used by utilities: /bin/bash, /bin/csh, /bin/jsh, /bin/ksh, /bin/ksh93, /bin/pfcsh, /bin/pfksh, /bin/pfsh,
       /bin/sh, /bin/tcsh, /bin/zsh, /sbin/jsh, /sbin/sh, /usr/bin/bash, /usr/bin/csh, /usr/bin/jsh, /usr/bin/ksh, /usr/bin/ksh93, /usr/bin/pfcsh,
       /usr/bin/pfksh, /usr/bin/pfsh, and /usr/bin/sh, /usr/bin/tcsh, /usr/bin/zsh, and /usr/sfw/bin/zsh. /etc/shells overrides the default list.

       Invalid shells in /etc/shells could cause unexpected behavior, such as being unable to log in by way of ftp(1).

FILES

       /etc/shells    list of shells on system

SEE ALSO

       vipw(1B), ftpd(1M), sendmail(1M), getusershell(3C), aliases(4)

SunOS 5.11							    20 Nov 2007 							 shells(4)
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