How to write a daemon script?

UNIX for Beginners Q & A
1

My requirement is to run two scripts simultaneously.
Let say, script1.ksh is running in a loop :
example:
script1.ksh is:

for i in 1 2 3
do
    script2.ksh 1 &
  #psedu code which is required to write here
  # if script 2.ksh is running, execute a script3.ksh (which actually check the status of a table)
  # And if script2.ksh still running sleep for 60 seconds and again check the status by script3.ksh
  #Means in every 60 seconds scripts3.ksh needs to execute until script2.ksh finishes
  #once script2.ksh is not running, go at the for loop to run with next parameter to fire the script2.ksh
  # script2.ksh 2 &
done
--
script2.ksh
echo "Script 2 is running, which is actually a long running data processing script and updating the status of a table"
-----

Note: & I tried to run in background to note down the PID ($$) and tried to build the logic but as soon as I execute in background (&), it is not working properly. And if I don't run in background then it waits until script2.ksh finishes and its too late to check the staus that time via status3.ksh.

Hope I am able to explain the complex requirements.
Your help is highly appreciated.

Thanks,
Sumit

2

What "is not working properly"? Executing (long running) scripts in background is standard and should not lead to problems.

3

Like this?

for i in 1 2 3
do
  script2.ksh $i &
  # if script 2.ksh is running, execute a script3.ksh (which actually check the status of a table)
  # And if script2.ksh still running sleep for 60 seconds and again check the status by script3.ksh
  while pgrep -f "script2.ksh $i"
  do
    script3.ksh
    sleep 60
  done
  #every 60 seconds scripts3.ksh needs to execute until script2.ksh finishes
  #once script2.ksh is not running, go at the for loop to run with next parameter to fire the script2.ksh
done