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Old 03-28-2012, 09:41 PM
Mark LaPierre
 
Default Fwd: parallel bash scripts

Hi mark.

I have a series of php apps that are async, and modify different tbls
within a mysql db. The php apps also perform other tasks as well.

The process needs to be able to periodically run the php apps. The
shell scripts are used to run the individual php apps. During testing,
I wanted to be able to run the apps, in a background manner, as well
as display the output for debugging.

The system has ~5-10 php apps that will be running.

The overall goal for all of this is part of a targeted web crawler,
where the php apps perform backend processing to manage the data from
the crawling process as it gets stored in the database.

So the process should fire up all of the processes, and they should
then run every X secs... At least thats the way I ultimately want it
to work. But I'm unable to figure out how to do this, and at the same
time, display the output for the debugging process...

Hopefully I've done a better job of explaining some of what this is for..



On Tue, Mar 27, 2012 at 10:23 PM, Mark LaPierre <marklapier@aol.com> wrote:

I don't understand what you are trying to do.

Do you want to run these commands in series? Run one, wait for it to
complete, then start the other?

If that's where you want to go then leave off the trailing ampersand but
keep the redirection. The output of the first program will appear in the
terminal due to the redirection. When the first program ends the second
program will start. That one needs redirection of standard out to standard
error too so that it's output will appear in the terminal as well.

Solution with trailing ampersand is appropriate for endless loops.
Solution without trailing ampersand is appropriate for serial operation.

I put the loop counter in the demo program just to stop the thing without
having to us ps and kill. Without the loop counter they will continue to
print inter-twined messages forever.

Does the program webservice_setup.sh start programs itself that you are
trying to read the output from? Are they correctly redirected to send their
standard output to standard error?


On 03/27/2012 10:01 PM, bruce wrote:


Hi mark.

the following is part of what i have tried... and what isn't working.
i changed the test shell scripts to no longer have infinite loops.
they simply execute the php app one time.

however, it still doesn't work.

in the initial shell script, it calls a php app that does some mysql
processes. the php app has a number of echo/print msgs to track what's
going on for testing.. when running as a background process the shell
script/php app isn't working.

the cmdline sits.. when i select the "return" key.. the process is
diplayed as being stopped...

if i remove the background "&" the shell script runs...

#### -- not working
/apps/parseapp2/webservice_setup.sh 1>&2&

#### -- works
/apps/parseapp2/webservice_setup.sh

/apps/parseapp2/webservice_setup.sh
-------------------------------
echo "starting the osu webservice test"
mysql -uroot1 -pfoo< /apps/parseapp2/setup_tblDb.sql
mysql -uroot1 -pfoo< /apps/parseapp2/webservice/webservice_tbls.sql
/apps/parseapp2/parse_tbl_setup.php
echo "started the osu webservice test"


thoughts???

thanks





On Tue, Mar 27, 2012 at 9:37 PM, Mark LaPierre<marklapier@aol.com> wrote:


Check out the redirection at the end of each command. 1>&2 redirects the
standard out of your child command to the standard error which then
appears
in the parent shell. At the end the last& launches your command into a

background shell and then moves on to launch the next command. The
redirections don't care if the command ever terminates.

The result is that both commands are launched and the parent shell
terminates leaving the standard error attached to the terminal that the
parent was launched in.


On 03/27/2012 09:08 PM, bruce wrote:



marklapier@aol.com

hey mark....

what you have, appears to be pretty close to what i had... except my
tests never ended... the loops are infinite...

can i do a fpaste and have you take a look at what i have?

-btuce


On Tue, Mar 27, 2012 at 9:00 PM, Mark LaPierre<marklapier@aol.com>
wrote:



On 03/27/2012 05:25 PM, bruce wrote:




hi.

got a couple of test bash scripts.

dog.sh, cat.sh
each script runs the underlying php in an endless loop.

I'm trying to figure out how to run the scripts in parallel, from the
same parent shell script. something like:

test.sh


where dog.sh would be :
--------------------------------
while true
do
pgrep dog
if [ $? -ne 0 ]
then
/dog.php
fi
sleep 5
done

my current tests, run dog.sh, which runs the dog.php ... but the test
never gets to run cat.sh

thoughts/comments...

thanks




Hey Bruce,

Do you mean to run these subprograms in parallel or in series?

cat.sh
#! /bin/bash

CAT=0
until [ $CAT -eq 10 ]
do
echo "Inside a dog it's too dark to read. $CAT"
CAT=$[$CAT + 1]
sleep 2
done


dog.sh
#! /bin/bash

DOG=0
until [ $DOG -eq 10 ]
do
echo "Next to a dog a book is man's best friend. $DOG"
DOG=$[$DOG + 1]
sleep 2
done


test.sh
#! /bin/sh

/home/mlapier/test/dog.sh 1>&2&
/home/mlapier/test/cat.sh 1>&2&


[mlapier@mushroom test]$ ./test.sh
[mlapier@mushroom test]$ Next to a dog a book is man's best friend. 0
Inside a dog it's too dark to read. 0
Next to a dog a book is man's best friend. 1
Inside a dog it's too dark to read. 1
Next to a dog a book is man's best friend. 2
Inside a dog it's too dark to read. 2
Next to a dog a book is man's best friend. 3
Inside a dog it's too dark to read. 3
Next to a dog a book is man's best friend. 4
Inside a dog it's too dark to read. 4
Next to a dog a book is man's best friend. 5
Inside a dog it's too dark to read. 5
Next to a dog a book is man's best friend. 6
Inside a dog it's too dark to read. 6
Next to a dog a book is man's best friend. 7
Inside a dog it's too dark to read. 7
Next to a dog a book is man's best friend. 8
Inside a dog it's too dark to read. 8
Next to a dog a book is man's best friend. 9
Inside a dog it's too dark to read. 9



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