simple shell script question. please give me advise - linux

Question

i have a question about simple shell script.
this is the source code of rand.sh below
#!/bin/bash
n=$(( RANDOM % 100 ))
if [[ n -eq 42 ]]; then
echo "Something went wrong"
>&2 echo "The error was using magic numbers"
exit 1
fi
echo "Everything went accrding to plan"
and i'm going to make a new shell script, let me call it quiz.sh.
quiz.sh should loop until n==42. if n==42, save the stdout("Something went wrong") and stderr("The error was using magic numbers")
and it finally terminated with printing out those stdout,stderr and Total execution count.
here is my quiz.sh
#!/bin/bash
cnt=0
while [[ "${n}" -ne 42 ]]
do
(( cnt = "${cnt}"+1 ))
source ./rand.sh &> error.txt
done
cat error.txt
echo "${cnt}"
but this is not working. because of exit 1 in rand.sh, the program is terminated before executing cat and echo which is at the end two line.
how can i fix it?? please let me know!

Answer 1

I want to make happen cat error.txt and echo "${cnt}" as well
Run the loop in a subshell
(
while something; do
something
exit 1 # exits only from the subshell
done
)
Note: parent shell doesn't access/inherit child process environment. So cnt is going to be empty in parent shell. Transfer it some other way.
(
cnt=0
while ((n != 42)); do
((cnt++))
echo "$cnt" > cntfile.txt
# >& is deprecated
source myrand > error.txt 2>&1
done
)
cnt=$(<cntfile.txt)
cat error.txt
echo "$cnt"
Reference Bash manual command grouping.

Answer 2

As KamilCuk pointed out correctly, you should use $n instead of n.
Furthermore, I personally would add that using source ./rand.sh &> error.txt is kind of weird in this case. If you want to run it as a background process, use:
./rand.sh &> error.txt &
wait $! # $! is the pid
Otherwise, just make a function out of it:
#!/bin/bash
function myrand {
n=$(( RANDOM % 100 ))
if [[ n -eq 42 ]]; then
echo "Something went wrong"
>&2 echo "The error was using magic numbers"
return 1
fi
echo "Everything went accrding to plan"
return 0
}
cnt=0
while [[ "${n}" -ne 42 ]]
do
(( cnt = "${cnt}"+1 ))
myrand() &> error.txt
done
cat error.txt
echo "${cnt}"
p.s. code not tested, but I guess it works.