I recall on one O/S the ksh would run ksh scripts in the same pid, so you would see interactive background with wait, but in Solaris it is always a child process, and waits only for its own children. I ended up putting () around lines 2-$ to keep my environment from getting scrambled by my scripts.
I guess wait on LINUX waits for everything. I wonder if nohup helps to move the script away. It might be an interesting man page read or such, to find out whether it is waiting for all processes on the tty or on the process group. But yes, collecting pids and waiting for them one at a time is best, as you get the exit return $? of each child from "wait $child_pid".
If the exit status is not a biggie, or you check that through log files, you can skill the wait and monitor the children through shared stdout and stderr, like this:
This monitors not only the children but their children and so on, as long as they do not redirect both stdout and stderr. Even when "wait $child_pid" returns, the child may have antecedents still running, background or up-pipeline processes that close stdout but do not immediately exit, or someone down-pipeline exits cutting them off! $! is just the parent or last in pipeline pid.
Code:
sleep 99 | sleep 5 & wait $! # wait waits for sleep 5 but sleep 99 is still running.
(sleep 99 & sleep 5 ) & wait $! # wait waits for sleep 5 but sleep 99 is still running.
The ability of processes other than $! to get errors not reported on $? is one reason to rely on logs, or write a very attentive wrapper script to keep an eye on the children and report $? for all. Sometimes I get really formal, for money and my job security and all that. This is fine for interactive, but not so wise unattended:
Code:
cmd1|cmd2|cmd3
Code:
>$fail_log
(
cmd1
zret=$?
if [ $zret != 0 ]
then
echo cmd1 returned $zret >>$fail_log
fi
) | (
cmd2
zret=$?
if [ $zret != 0 ]
then
echo cmd2 returned $zret >>$fail_log
fi
) | (
cmd3 . . . .
)
if [ -s $fail_log ]
then
exit 1
fi
Last edited by DGPickett; 10-29-2010 at 12:52 PM..
This might be a bug in the version of ksh that you have which is likely fixed in the current release.
I'm running 'Version JM 93t+ 2009-02-02' on some boxes, and 'Version JM 93t+ 2010-06-21' on most of my linux boxes. Testing on the older of the two it handled your script without any problems:
Code:
>>>start: Sun Oct 31 23:18:46 EDT 2010
jobs output
[2] + Running <command unknown>
[1] - Running <command unknown>
jobs -p
Before entering parallel process 18154
>>>finish: Sun Oct 31 23:18:46 EDT 2010
I added start/finish messages to show the delay, if there was any. There is a more recent release than the 6/21/2010 version; it can be pulled direcly from AT&T Labs-Research; AST software download
As a further test, I put this little script together that reads lines with one or more sleep times and sets that many async sleep processes going. It is similar to the script you are running and it seems to have no issues with a more recent version of ksh.
Code:
while read list
do
for x in $list
do
echo "$(date) sleeping $x"
sleep $x &
done
echo "$(date) waiting"
wait
echo "$(date) looping"
done <xx
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#!/bin/sh
# This script returns the number of rows updated from a function
echo "The execution is starting ....."
sqlplus -silent $UP <<EOF
set serveroutput on
set echo off
set pagesize 0
VAR no_rows_updated NUMBER;
EXEC :no_rows_updated :=0;
DECLARE
CURSOR c_update is
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11-01-2010
