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Full Discussion: Passing a variable from a child script back to the parent
Top Forums Shell Programming and Scripting Passing a variable from a child script back to the parent Post 302199340 by mstephens on Monday 26th of May 2008 04:32:58 PM
Old 05-26-2008
Quote:
Originally Posted by Andy82
Hi

I have written a script using ftp to get files from one server and copy them to 2 dirrerent servers. I wish to call this script from a parent script that will check the number of files copied and run a check sum for each file. As the filenames for the files in the get portion of the script are hard coded into the child script is it possible to pass these files names from the child back to the parent. I have seen some error checking examples but no examples of variable being passed back.

Any help would be greatly appreciated.

Andy, If you use ksh93 this will work.

Stick your child scripts into functions - or at least have functions which run the child scripts using the . operator so that they are running within the same process as the main script.

then do something like below:
------------------------------------------

function afunc
{
# This is the function which either contains the child script or calls it using # the . operator

# the line below makes parameter 1 a by reference parameter
typeset -n pFilename=$1
..
..
.. script sets vValue to a filename received by FTP somewhere in here
.. for example vValue="receivedfile.txt"
pFilename=$vValue

return 0
}

# The main script is here
..
..
..
# lets call the function
afunc vFilename
# note that vFilename = $1 in afunc and will point to the same memory address as pFilename variable in the function
echo $vFilename
# which miraculously will turn out to be "receivedfile.txt"
-------------------------------------------------------------

You could do something similar with ksh bash or sh but that would work because all the variables of scripts using the same process are global - some versions of bash may have ksh93 features though.

If you must use scripts which don't use the same processes then the following will work:

#---- Calling script--------
..
..
# call the child script
childscript.sh
avar=`cat afile`
echo $avar
..
..
#---end of calling script-------------------

#---childscript.sh---------------
..
.. bvar="receivedfile.txt" happens somewhere in here
..
echo $bvar > afile
#------ end of childscript.sh
 

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LEARN ABOUT SUNOS

script

script(1)							   User Commands							 script(1)

NAME

       script - make record of a terminal session

SYNOPSIS

       script [-a] [filename]

DESCRIPTION

       The  script  utility  makes a record of everything printed on your screen. The record is written to filename. If no file name is given, the
       record is saved in the file typescript. See WARNINGS.

       The script command forks and creates a sub-shell, according to the value of $SHELL, and records the text from this session. The script ends
       when the forked shell exits or when Control-d is typed.

OPTIONS

       The following option is supported:

       -a	Appends the session record to filename, rather than overwriting it.

NOTES

       script places everything that appears on the screen in filename, including prompts.

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |CSI			     |Enabled			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       attributes(5)

WARNINGS

       script  can  pose  a  security risk when used in directories that are writable by other users (for example, /tmp), especially when run by a
       privileged user, that is, root. Be sure that typescript is not a link before running script.

SunOS 5.10							    30 Jan 2004 							 script(1)
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