can I multiply delimiter of array in bash

Question

I need to divide the arrays. I have made this code:

systemHosts=(here the list on hosts which is around 700 positions)
openSSHlineLimit=1024
systemHostsLength=${#systemHosts[@]}
systemHostsByteLength=$(echo ${systemHosts[@]} | wc -c)
let divideBy=$systemHostsByteLength/$openSSHlineLimit
let modu=$systemHostsByteLength%$openSSHlineLimit
if [[ $divideBy == 0 ]] && [[ $modu != 0 ]]; then
    echo "
host   ${systemHosts[@]}
    user system
        "  #> ~/.ssh/config
elif [[ $divideBy == 1 ]] && [[ $modu > 0 ]]; then
    let getBreak=$systemHostsLength/2
    echo "
host   ${systemHosts[@]::$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak}
    user system
        "  # >> ~/.ssh/config
elif [[ $divideBy == 2 ]] && [[ $modu > 0 ]]; then
    let getBreak=$systemHostsLength/3
    echo "
host   ${systemHosts[@]::$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak:$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak*2}
    user system
        "  # > ~/.ssh/config
elif [[ $divideBy == 3 ]] && [[ $modu > 0 ]]; then
    echo "
host   ${systemHosts[@]::$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:($getBreak:$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak*3:$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak*4}
    user system
        "  # > ~/.ssh/config
elif [[ $divideBy == 4 ]] && [[ $modu > 0 ]]; then
    echo "
host   ${systemHosts[@]::$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak*2:$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak*3:$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak*4:$getBreak}
    user system
        "  # > ~/.ssh/config
    echo "
host   ${systemHosts[@]:$getBreak*5}
    user system
        "  # > ~/.ssh/config
fi

those parts:

${systemHosts[@]:$getBreak*2:$getBreak}
${systemHosts[@]:$getBreak*3:$getBreak}
${systemHosts[@]:$getBreak*4:$getBreak}

does not really work however this

${systemHosts[@]:$getBreak*2}

works perfectly well

I it that the expression ...[@]:$var*n:$var is not allowed or I do something wrong?

. . . . . . . . . . UPDATE / SOLUTION / . . . . . . . . . .

Hi. I write in here as I blocked answaring for this questin :< the script did not work because I forgot to add:

let getBreak=$systemHostsLength/<divider>

on the beginning of each elif :/ Sorry for bothering and thanks a lot for all the answares ;)

Answer 1

It seems you are mixing length in bytes and array size :

let divideBy=$systemHostsByteLength/$openSSHlineLimit
let modu=$systemHostsByteLength%$openSSHlineLimit

depending on length of names can give different values for divideBy and modulo, and may not execute no if branch.

$ is not required in arithmetic context:

## example
arr=(host-{1..25})
for ((i=0;i<5;i+=1)); do echo ${arr[@]:5*i:5}; done