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Full Discussion: How do you wait for command substitution processes to complete?
Top Forums UNIX for Dummies Questions & Answers How do you wait for command substitution processes to complete? Post 302397993 by mrvwman on Tuesday 23rd of February 2010 02:23:10 PM
Old 02-23-2010
wait & sleep
wait doesn't work, I tried that. sleep might work most of the time, but it isn't a guarantee that the work would be done after sleeping.

I wrote up the following to do what I want, it works but I guess I was hoping for a more elegant solution like a simple flag for wait or something.

Code:
#!/bin/bash

DONE_PIPE=/tmp/donepipe$$
mkfifo $DONE_PIPE
exec 7<>$DONE_PIPE

zcat /logs/billing.log.2009/09/01/billing.log.20090901_101924.96.17.157.45.gz | tee >(wc && echo "HELLO" && echo "DONE" >&7) > /dev/null
COUNTER=0
#wait for the processors to complete
while [ $COUNTER -lt 1 ]; do
    read LINE <&7
    echo $LINE
    let COUNTER=COUNTER+1
done

exec 7>&-
exec 7<&-

rm $DONE_PIPE

echo "WORLD"

Which produces the following output:
Code:
22245  175374 3598423
HELLO
DONE
WORLD

With the above code multiple >(cmd) arguments can be given to tee and each would echo a statement to the 7 filedescriptor when they're complete. The while loop condition would just be adjusted to wait for however many processes you have launched using >(cmd).
 

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LEARN ABOUT SUNOS

gst-complete-0.8

gst-complete-0.8(1)						   User Commands					       gst-complete-0.8(1)

NAME

       gst-complete-0.8, gst-complete - perform bash completion for gst-launch command lines

SYNOPSIS

       complete -Cgst-complete-0.8 gst-launch

       gst-complete [--gst-list-mm] [--gst-mm=string] [--print]

DESCRIPTION

       gst-complete-0.8 enables bash to provide context-sensitive tab completion for gst-launch command lines. See gst-launch(1) for the syntax of
       gst-launch command lines.

       You must have a version of bash that supports programmable completion. Such versions of bash provide the complete built-in command.

       gst-complete is a wrapper script that runs the latest installed version of gst-complete-X.X. For example, if both gst-complete-0.7 and gst-
       complete-0.8 are installed on your system, gst-complete runs gst-complete-0.8.

OPTIONS

       The following options are supported by gst-complete-0.8 and gst-complete:

       --help	       Display detailed usage message. You can also use -? to specify this option.

       The following options are supported by gst-complete only:

       --gst-list-mm   List found major/minor versions. This option displays the versions that are available.

       --gst-mm=string Force  major/minor  version.  This  option  enables you to specify a specific version to run, if you do not want to run the
		       default version.

       --print	       Print wrapped command line. This option displays the command that will be run, and then runs the command.

EXAMPLES

       Example 1: Generating the Registry of Available Plugins by Running gst-compprep

       Run the following command in your .bash_profile or other appropriate place:

       example% complete -C gst-complete-0.8 gst-launch

       Example 2: Running the Wrapper Script and Displaying the Command Name

       example% gst-complete --print
       /usr/bin/gst-complete-0.8

FILES

       The following files are used by this application:

       /usr/bin/gst-complete-0.Executable for bash completion for gst-launch

       /usr/bin/gst-complete   Wrapper script that runs the latest installed version of gst-complete-X.X

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWgnome-media		   |
       +-----------------------------+-----------------------------+
       |Interface stability	     |External			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       gst-compprep(1), gst-feedback(1), gst-inspect(1), gst-launch(1), gst-launch-ext(1), gst-md5sum(1), gst-register(1), gst-thumbnail(1),  gst-
       typefind(1), gst-xmlinspect(1), gst-xmllaunch(1), gstreamer-properties(1), libgstreamer-0.8(3), libgstgetbits(3)

NOTES

       Original man page written by the GStreamer team at http://gstreamer.net/.

       Updated by Brian Cameron, Sun Microsystems Inc., 2004.

SunOS 5.10							    14 Oct 2004 					       gst-complete-0.8(1)
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