Is there in bash scripts a way of using variables to specify different bash arrays

For example in this simple script

#!/bin/bash

declare -a MYARRAY1
declare -a MYARRAY2

function updatearray {
ARRAY=$1
VALUE=$2

$ARRAY+=$VALUE

}

updatearray MYARRAY1 "yyyy "
updatearray MYARRAY2 "bbbb "

echo "${MYARRAY1[@]}"
echo "${MYARRAY2[@]}"

exit 0

Just results in "line 10: MYARRAY1+=yyyy: command not found" rather than updating the array. This is actually for a more complex bash script I'm working on that has more arrays I want to update, so I'm hoping to avoid 'case' statements which would mean a big function body

I guess you could

eval $ARRAY+=$VALUE

But I wouldn't recommend doing this. I believe you should rethink/rewrite the script to avoid this level of indirecton.

Thanks for the quick reply shruggy

You have overlooked a couple of things.
Frankly, passing by reference should fix those things painlessly.
Try something (untested) like this

#!/bin/bash

declare -a MYARRAY1
declare -a MYARRAY2

function updatearray () {

   local -n  arr=$1 
   local VALUE="$2"

  arr+="${VALUE}"
}

updatearray MYARRAY1 "yyyy "
updatearray MYARRAY2 "bbbb "

echo "${MYARRAY1[@]}"
echo "${MYARRAY2[@]}"

exit 0

See if that works better, or gives a more useful error at least.

Thanks wpeckham, (near) perfect!

#!/bin/bash

declare -a MYARRAY1
declare -a MYARRAY2

function updatearray () {

   local -n  arr=$1 
   local VALUE="$2"

  arr+=("${VALUE}")
}

updatearray MYARRAY1 "yyyy" <- trailing space not req'd for array assignment
updatearray MYARRAY1 "zzzz"
updatearray MYARRAY2 "bbbb"

echo "${#MYARRAY1[@]}"
echo "${MYARRAY1[@]}"

echo "${#MYARRAY2[@]}"
echo "${MYARRAY2[@]}"

exit 0

My bash is v4.3.048

FYI: My bash is 5.1.8 but I pulled this mostly off the top of my head. (Which mostly runs BASH 4.1!) ;-)

Thanks everyone, you've been a great help

I used a hybrid solution in the end. Unfortunately my bash is pretty ancient (unfortunately not under my control) at
GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)

So the "local -n" errored and it failed

I'm using this at the moment.

#!/bin/bash

declare -a MYARRAY1
declare -a MYARRAY2

function updatearray {
ARRAY=$1
VALUE=$2

eval $ARRAY+="${VALUE}"

}

updatearray MYARRAY1 "yyyy"
updatearray MYARRAY2 "bbbb"

echo "array 1"
echo "${MYARRAY1[@]}"
echo "array 2"
echo "${MYARRAY2[@]}"

exit 0

Which works fine.

I doubt that.
You need the parentheses in the array assignment, as it was mentioned ealier.
Here comes a fix, and a more comprehensive test:

declare -a MYARRAY1
declare -a MYARRAY2

function updatearray {
ARRAY=$1
VALUE=$2

eval $ARRAY+='("${VALUE}")'

}

updatearray MYARRAY1 "yyyy"
updatearray MYARRAY1 "zz z"
updatearray MYARRAY2 "bbbb"

echo "array 1"
printf "(%s)\n" "${MYARRAY1[@]}"
echo "array 2"
printf "(%s)\n" "${MYARRAY2[@]}"

thanks

thank you

Originally Posted by Ida11 thanks

reported