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Full Discussion: Shell Script behaviour and syntax
Top Forums UNIX for Beginners Questions & Answers Shell Script behaviour and syntax Post 303045796 by Cybora on Monday 13th of April 2020 03:45:46 PM
Old 04-13-2020
Shell Script behaviour and syntax
Here are the 3 scripts(FirstScrpt.sh,firstcallScrpt.sh,startProcess.sh) that were running in the server for the past several years.
I understand the way it is written is that for every 1 hour 'firstcallScript.sh' is being called in that it kills the pid of 'startProcess.sh'
and starts again.

2 things I noticed
1. Value of pid.txt never changes if it is being is killed and created every hour.
2. It never runs in the background even when it is run with '&' like (./FirstScrpt.sh &)

FirstScrpt.sh
Code:
#!/bin/bash

if [ $# -ne 1 ]
then
	echo "Usage:  $0 test|prod"
	exit 1
fi
envRun=$1

  echo "Level is :  ${envRun}"
	while [ 1 ]
	do
	cat pid.txt | xargs -l1 kill
	./firstcallScript.sh ${envRun}
	sleep 3600
	done

firstCallScript.sh
Code:
#!/bin/bash

if [ $# -ne 1 ]
then
	echo "Usage:  $0 test|prod"
	exit 1
fi
envRun=$1

if [ $envRun = "test" ] 
then
  echo "Level is  :  ${envRun}"
     ./startProcess.sh ${envRun}
   
 else
   echo "Level is test Invoke test script :  ${envRun}"
   	./startProcess.sh ${envRun}
	
fi

startProcess.sh

Code:
#!/bin/bash 
envRun=$1
echo "${envRun}"
echo "I'm a Linux user."
echo $! > pid.txt

Last edited by Cybora; 04-13-2020 at 04:53 PM.. Reason: Edited the firstScript for 1 hour of sleep
 

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LEARN ABOUT CENTOS

pppoe-connect

PPPOE-CONNECT(8)					      System Manager's Manual						  PPPOE-CONNECT(8)

NAME

       pppoe-connect - Shell script to manage a PPPoE link

SYNOPSIS

       pppoe-connect [config_file]

       pppoe-connect interface user [config_file]

DESCRIPTION

       pppoe-connect  is  a  shell  script  which  manages a PPPoE connection using the Roaring Penguin user-space PPPoE client.  If you omit con-
       fig_file, the default file /etc/sysconfig/network-scripts/ifcfg-ppp0 is used.  If you supply interface and user,  then  they  override  the
       Ethernet interface and user-name settings in the configuration file.

       Note that normally, you should not invoke pppoe-connect directly.  Instead, use pppoe-start to bring up the PPPoE connection.

       pppoe-connect  first  reads a configuration file.  It then brings up a PPPoE connection.  If the connection ever drops, a message is logged
       to syslog, and pppoe-connect re-establishes the connection.  In addition, each time the connection is dropped  or  cannot  be  established,
       pppoe-connect executes the script /etc/ppp/pppoe-lost if it exists and is executable.

       The shell script pppoe-stop causes pppoe-connect to break out of its loop, bring the connection down, and exit.

TECHNICAL DETAILS

       pppoe-connect uses the following shell variables from the configuration file:

       ETH    The Ethernet interface connected to the DSL modem (for example, eth0).

       USER   The PPPoE user-id (for example, b1xxnxnx@sympatico.ca).

       PIDFILE
	      A file in which to write the process-ID of the pppoe-connect process (for example, /var/run/pppoe.pid).  Two additional files ($PID-
	      FILE.pppd and $PIDFILE.pppoe) hold the process-ID's of the pppd and pppoe processes, respectively.

       By using different configuration files with different PIDFILE settings, you can manage multiple PPPoE connections.  Just specify  the  con-
       figuration file as an argument to pppoe-start and pppoe-stop.

AUTHOR

       pppoe-connect was written by David F. Skoll <dfs@roaringpenguin.com>.

       The pppoe home page is http://www.roaringpenguin.com/pppoe/.

SEE ALSO

       pppoe(8),  pppoe-start(8),  pppoe-stop(8), pppd(8), pppoe.conf(5), pppoe-setup(8), pppoe-status(8), pppoe-sniff(8), pppoe-server(8), pppoe-
       relay(8)

4th Berkeley Distribution					 21 February 2000						  PPPOE-CONNECT(8)
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