Shell script: How to loop run two programs? - bash

Question

I'm running an Ubuntu server to mine crypto. It's not a very stable coin yet and their main node gets disconnected sometimes. When this happens it crashes the program through fatal error.
At first I wrote a loop script so it would keep running after a crash and just try again after 15 seconds:
while true;
do ./miner <somecodetoconfiguretheminer> &&break;
sleep 15
done;
This works, but is inefficient. Sometimes the loop will keep running for 30 minutes until the main node is back up - which costs me 30 minutes of hashing power unused. So I want it to run a second miner for 15 minutes to mine another coin, then check the first miner again if its working yet.
So basically: Start -> Mine coin 1 -> if crash -> Mine coin 2 for 15 minutes -> go to Start
I tried the script below but the server just becomes unresponsive once the first miner disconnects:
while true;
do ./miner1 <somecodetoconfiguretheminer> &&break;
timeout 900 ./miner2
sleep 15
done;
Ive read through several topics / questions on how &&break works, timeout works and how while true works but I can't figure out what I'm missing here.
Thanks in advance for the help!

Answer 1

A much simpler solution would be to run both of the programs all the time, and lower the priority of the less-preferred one. On Linux and similar systems, that is:
nice -10 ./miner2loop.sh &
./miner1loop.sh
Then the scripts can be similar to your first one.

Answer 2

Okay, so after trial and error - and some help - I found out that there is nothing wrong with my initial code. Timeout appears to behave differently on my linux instance when used in terminal than in a bash script. If used in Terminal it behaves as it should, it counts down and then kills the process it started. If used in bash however - it acts as if I typed 'sleep' and then after counting down stops.
Apparently this has to do with my Ubuntu instance (running on a VPS). Even though I installed latest versions of coreutils, have all the latest versions installed through apt-get update etc. This is the case for me on Digital Ocean as well as Google Compute.
The solution is to use the Timeout code as a function within the bash script, as found on another thread in stackoverflow. I named the function timeout2 as to not confuse the system in triggering the not properly working timeout command:
#!/bin/bash
# Executes command with a timeout
# Params:
# $1 timeout in seconds
# $2 command
# Returns 1 if timed out 0 otherwise
timeout2() {
time=$1
# start the command in a subshell to avoid problem with pipes
# (spawn accepts one command)
command="/bin/sh -c "$2""
expect -c "set echo "-noecho"; set timeout $time; spawn -noecho
$command; expect timeout { exit 1 } eof { exit 0 }"
if [ $? = 1 ] ; then
echo "Timeout after ${time} seconds"
fi
}
while true;
do
./miner1 <parameters for miner> && break;
sleep 5
timeout2 300 ./miner2 <parameters for miner>
done;