Pass the value from pipe Post: 302940444

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Top Forums Shell Programming and Scripting Pass the value from pipe Post 302940444 by Don Cragun on Sunday 5th of April 2015 10:50:14 PM

04-05-2015

Registered User

Just as date printed three values that you used read to import into the second stage of your pipeline, you need to print the results you want to export from the second stage of your pipeline and read the results in the third stage of your pipeline. The third stage of your pipeline is not in a subshell environment of the execution environment of the second stage of your pipeline; so variables exported in the second stage of your pipeline are not visible in the third stage of your pipeline.

Code:

date '+%m %d %Y' |
{
read MONTH DAY YEAR
DAY=`expr "$DAY" - 1`
case "$DAY" in
        0)
                MONTH=`expr "$MONTH" - 1`
                        case "$MONTH" in
                                0)
                                        MONTH=12
                                        YEAR=`expr "$YEAR" -1`
                                ;;
                        esac
                DAY=`cal $MONTH $YEAR | grep . | fmt -1 | tail -1`
esac
vardt=$?
if [ $vardt -ne 0 ];then
        echo "ERROR DURING SPOOLING PREVIOUS DAY DATE."
        exit 1
fi
echo "${MONTH}/${DAY}/${YEAR}"
} |
{
read YDAY
export YDAY
echo $YDAY
}

Last edited by Don Cragun; 04-06-2015 at 05:34 PM.. Reason: Put export and echo at end of script in a subshell.

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LEARN ABOUT DEBIAN

pidof

PIDOF(8)						Linux System Administrator's Manual						  PIDOF(8)

NAME

       pidof -- find the process ID of a running program.

SYNOPSIS

       pidof [-s] [-c] [-n] [-x] [-o omitpid[,omitpid..]]  [-o omitpid[,omitpid..]..]  program [program..]

DESCRIPTION

       Pidof  finds  the  process  id's (pids) of the named programs. It prints those id's on the standard output. This program is on some systems
       used in run-level change scripts, especially when the system has a System-V like rc structure. In that case these scripts  are  located	in
       /etc/rc?.d, where ? is the runlevel. If the system has a start-stop-daemon (8) program that should be used instead.

OPTIONS

       -s     Single shot - this instructs the program to only return one pid.

       -c     Only  return  process ids that are running with the same root directory.	This option is ignored for non-root users, as they will be
	      unable to check the current root directory of processes they do not own.

       -n     Avoid stat(2) system function call on all binaries which are located on network based file systems like NFS.  Instead of using  this
	      option the the variable PIDOF_NETFS may be set and exported.

       -x     Scripts too - this causes the program to also return process id's of shells running the named scripts.

       -o omitpid
	      Tells  pidof  to omit processes with that process id. The special pid %PPID can be used to name the parent process of the pidof pro-
	      gram, in other words the calling shell or shell script.

EXIT STATUS

       0      At least one program was found with the requested name.

       1      No program was found with the requested name.

NOTES

       pidof is actually the same program as killall5; the program behaves according to the name under which it is called.

       When pidof is invoked with a full pathname to the program it should find the pid of, it is reasonably safe. Otherwise it is  possible  that
       it  returns  pids  of  running programs that happen to have the same name as the program you're after but are actually other programs. Note
       that that the executable name of running processes is calculated with readlink(2), so symbolic links to executables will also match.

SEE ALSO

       shutdown(8), init(8), halt(8), reboot(8), killall5(8)

AUTHOR

       Miquel van Smoorenburg, miquels@cistron.nl

								    01 Sep 1998 							  PIDOF(8)