While IFS loop continue when less than 5 terminals open

Question

I have loop function:

while IFS='|' read -r keyword; do
      xterm -e "echo -ne '\e[8;5;60t'; program -command"
done < ./filename

I need to open only 5 terminals with program -command but when one terminal do the job and close then loop should start open again until 5 opened windows.

I try

[ $( jobs | wc -l ) -ge 5 ] && wait

But after one is done job only 4 is open and this wait to the last one until is open and start again 5 times.

Maybe some can modify this scirpt to work

while [ `ps -p ${pid1},${pid2} | wc -l` < 5 ]
do
  sleep 1
done

This scirpt run every one second new terminal...

while IFS='|' read -r keyword; do
      xterm -e "echo -ne '\e[8;5;60t'; program -command" &
      sleep 1
done < ./filename

But i need something to check if there are opened 5x terminals if not then run loop one more time.

while IFS='|' read -r keyword; do
      xterm -e "echo -ne '\e[8;5;60t'; program -command"
      # Script to block loop until less than 5 terminal are open
      while [ `ps -p ${pid1},${pid2} | wc -l` < 5 ]
      do
        echo "There is less than 5 terminals opened"
      done
done < ./filename

I found something like this, how to modify this?

while [  $(ps -ef | grep KEYWORD | grep -v grep | wc -l) -gt 0 ]; do
sleep 1
done

I made script

        child_count=$(($(pgrep --parent $$ | wc -l) - 1))
        if [ "$child_count" -lt "5" ]; then
            echo "Opened terminals: $child_count"
        else [ "$child_count" -ge "5" ]
            echo "Too many termianls: $child_count"; wait
        fi

But still is waiting until all finished, this should check every 10 sec if one terminal is less than 5

I found solution:

        check_processes(){
            while true; do
                child_count=$(($(pgrep --parent $$ | wc -l) - 1))
                if [ "$child_count" -lt "5" ]; then
                    echo "Opened terminals: $child_count"
                break
                else [ "$child_count" -ge "5" ]
                    echo "Too many termianls: $child_count"; sleep 10; check_processes
                fi
            done
            }
        check_processes

Answer 1

This code segment will create five xterm windows. As you kill them off another one will be spawned.

#!/bin/bash
#
pids=()

# Eternal loop
while :
do
    if [[ ${#pids[@]} -lt 5 ]]
    then
        # Start another process
        xterm &
        pid=$!

        # Save process id
        pids+=($pid)
    else
        # We have enough so wait for (at least) one to die
        wait -n

        # Reap old process ids
        oldpids=("${pids[@]}")
        pids=()
        n=0
        while [[ $n -lt ${#oldpids[@]} ]]
        do
            pid=${oldpids[$n]}
            [[ -n "$pid" ]] && kill -0 $pid 2>/dev/null && pids+=($pid)
            n=$((n+1))
        done
    fi
done