[SOLVED] Instantiating unique bash instances with their own PID from a single parent array

Issue

I was given a command "ChanDataStream_Sim" (on a linux box) that I need to run against 40 channels simultaneously. The command once executed runs indefinitely until someone manually kills the PID. Moreover the command will halt if interrupted or the session ended. A new dedicated PuTTy session would need to be launched for each channel we want to test.

What I would like to do is instantiate an instance of the command with EACH iteration of channel in my array. Essentially if I list 30 channels in my array, I'd like to see 30 instances (with their own PID) of the command line running. I want to avoid having the engineer open 40 PuTTy sessions just to run the thing or having to craft 40 tiny scripts if at all possible.

Desired outcome:

PID      User
1112     ChanDataStream_Sim+ <--- For Channel 3002
1113     ChanDataStream_Sim+ <--- For Channel 1001
1114     ChanDataStream_Sim+ <--- For Channel 4003
1115     ChanDataStream_Sim+ <--- For any additional channels in the array

Here's what I wrote so far.

#bash
#!/bin/bash

# all the channels to simulate data flow against.
channels=(3002 1001 4003)

# how fast the simulated data should hit the channel
priority=(IDLE REALTIME HIGH)

# selecting one of the 225 daemons available for the process to run against
objserv=(83 82 81)

length=${#channels[@]}
for (( i=0; i<$length; i++ ))
do

# running the command with the requisite channel variables
ChanDataStream_Sim ${channels[$i]} -d -p ${priority[$i]} -s ${objserv[$i]}
done

Any clues would be greatly appreciated.

Solution

Solution: This snippet creates iterations of the embedded command based on the number of channels in the array

#bash
#!/bin/bash
# Testing Channels: 1001, 2001, 2004

# Setting up my channels and openChan_sim controls
channels=(3002 1001 4003)
priority=(REALTIME REALTIME REALTIME)
objserv=(83 82 81)

# Get the length of one of the arrays
length=${#channels[@]}

# Function to perform the iteration in a subshell
perform_iteration() {
    local index=$1
    openChan_sim ${channels[$index]} -d -p ${priority[$index]} -s ${objserv[$index]}"
}

# Loop through the channels and create subshell instances
for ((i=0; i<length; i++))
do
    (perform_iteration "$i") &
done
wait

Answered By - NanoNet

Answer Checked By - Cary Denson (WPSolving Admin)