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simple while loop script to check a connection

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Top Forums Shell Programming and Scripting simple while loop script to check a connection
# 8  
Old 10-09-2012
Quote:
Originally Posted by zippyzip
Hi pamu

Thanks for your help so far. Essentially if program A is running i want to continually send serial keepalives to the serial port..(something is scooping this output up fine) if the program fails i want the output to stop.. if the program resumes i want it to continue

Thanks

Zippy
1)Is it possible to edit Program A..? If yes then you can just call your second script from program A.

2)Second way is use crontab for your script that check your Program A stastus after some specific time.

3)Third way you can use your program second in infinite loop.(not good way of programming, but if you wish.)

Code:
while true
do
Program second code
done

Hope this helps you..Smilie
# 9  
Old 10-10-2012
Hi Pamu,

Tried the following in /etc/cron.minutely

Code:
#!/bin/bash CONNECTED=$(ps -ef | grep -c APP1) while [ "$CONNECTED" -gt 1 ]; do   echo -n p >/dev/ttyS1;   echo $CONNECTED   CONNECTED=$(ps -ef | grep -c APP1) done

it seemed to work but killed the CPU.. ran top and 0% idle.. and lots defunct instances of ps ( see below)..
Code:
top - 18:00:58 up  1:32,  1 user,  load average: 114.69, 112.65, 100.98
Tasks: 741 total, 155 running, 554 sleeping,   0 stopped,  32 zombie
Cpu(s): 34.4%us, 64.3%sy,  0.0%ni,  0.0%id,  0.0%wa,  0.0%hi,  1.2%si,  0.0%st
Mem:   2075060k total,   442024k used,  1633036k free,    27356k buffers
Swap:  1052248k total,        0k used,  1052248k free,   205168k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                           
 7549 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7556 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7563 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7566 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7582 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7585 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7597 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7604 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7611 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7614 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7617 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7624 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7627 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7634 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7649 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7652 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7655 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7661 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>                                      
 7665 root      18   0     0    0    0 Z  1.3  0.0   0:00.05 ps <defunct>

Not sure whats wrong. Do you have any ideas?

Thanks

zippyzip

Moderator's Comments:
Mod Comment Please use code tags for code and data
Last edited by Scrutinizer; 10-10-2012 at 07:37 AM.. Reason: code tags
# 10  
Old 10-10-2012
you don't need while loop now...

just try with if

Code:
if [[ $(ps -ef | grep -c APP1) -gt 1]]
then
echo -n p >/dev/ttyS1
fi

that's what you need.
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