An example of how to deref arrays and use them

derefrence_arrays.bash

# SOURCE ME
# DOES NOT WORK WITH ELEMENTS CONTAINING SPACES!!!!
# Limited use. Use a real scriptting language!?!?
#   Ex:
#    declare -a cmplxArr='([0]="preffoo" [1]="bar" [2]="foo" [3]="prefbaz" [4]="baz" [5]="prefbar" [6]="pref with spaces" [7]="pref
#    with
#    new line" [8]="
#    pref with new line before")'


# Check to see if this bash version has derefernced arrays
unset refArr
if declare -n refArr ; then
  echo "Using a bash version that can dereference arrays (bash>=4.3)"

  # Dynamically create an array by name
  function arr_new() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -g -a $1=\(\)
  }

  # Insert incrementing by incrementing index eg. array+=(data)
  function arr_insert() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      declare -n r=$1
      r[${#r[@]}]=$2
  }

  # Update an index by position
  function arr_set() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      declare -n r=$1
      r[$2]=$3
  }

  # Get the array content ${array[@]}
  function arr_get() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      declare -n r=$1
      echo ${r[@]}
  }

  # Get the value stored at a specific index eg. ${array[0]}
  function arr_at() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      [[ ! "$2" =~ ^(0|[-]?[1-9]+[0-9]*)$ ]] && { echo "Array index must be a number" 1>&2 ; return 1 ; }
      declare -n r=$1
      local max=${#r[@]}
      # Array has items and index is in range
      if [[ $max -gt 0 && $i -ge 0 && $i -lt $max ]]
      then
          echo ${r[$2]}
      fi
  }

  # Get the value stored at a specific index eg. ${array[0]}
  function arr_count() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable " 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      declare -n r=$1
      echo ${#r[@]}
  }
else
  echo "Using a bash version that cannot dereference arrays (bash<4.3)"

  # Dynamically create an array by name
  function arr_new() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      # Note: For some reason when using 'declare -ag $1' without the parentheses will make 'declare -p' fail
      declare -ag $1=\(\)  # Could also be created with 'eval $1=\(\)'
  }

  # Insert incrementing by incrementing index eg. array+=(data)
  function arr_insert() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      eval $1[\$\(\(\${#${1}[@]}\)\)]=\$2
  }

  # Update an index by position
  function arr_set() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      eval ${1}[${2}]=\${3}
  }

  # Get the array content ${array[@]}
  function arr_get() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      eval echo \${${1}[@]}
  }

  # Get the value stored at a specific index eg. ${array[0]}
  function arr_at() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      [[ ! "$2" =~ ^(0|[-]?[1-9]+[0-9]*)$ ]] && { echo "Array index must be a number" 1>&2 ; return 1 ; }
      local v=$1
      local i=$2
      local max=$(eval echo \${\#${1}[@]})
      # Array has items and index is in range
      if [[ $max -gt 0 && $i -ge 0 && $i -lt $max ]]
      then
          eval echo \${$v[$i]}
      fi
  }

  # Get the value stored at a specific index eg. ${array[0]}
  function arr_count() {
      [[ ! "$1" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable " 1>&2 ; return 1 ; }
      declare -p "$1" > /dev/null 2>&1
      [[ $? -eq 1 ]] && { echo "Bash variable [${1}] doesn't exist" 1>&2 ; return 1 ; }
      local v=${1}
      eval echo \${\#${1}[@]}
  }

  # Remove array elements matching
  function arr_delete() {
      aName="$1"
      [[ ! "$aName" =~ ^[a-zA-Z_]+[a-zA-Z0-9_]*$ ]] && { echo "Invalid bash variable" 1>&2 ; return 1 ; }
      declare -p "$aName" > /dev/null 2>&1
      #[[ $? -eq 1 ]] && { echo "Bash variable [${aName}] doesn't exist" 1>&2 ; return 1 ; }
      arr=($(arr_get $aName))
      declare -p arr
      local regex=${2}
      for i in "${!arr[@]}" ; do [[ ${arr[$i]} =~ ${2} ]] && unset -v 'arr[$i]' ; done
      declare -p arr
      arr=("${arr[@]}") # Re-index the array
      #declare -p arr
      #echo $(echo ${aName})=\(${arr[@]}\)
      eval $(echo ${aName})=\(${arr[@]}\)
  }

fi

array_names=(bob jane dick)

for name in "${array_names[@]}" ; do
    arr_new dyn_$name
done

echo "Arrays Created"
declare -a | grep "a dyn_"

# Insert three items per array
for name in "${array_names[@]}" ; do
    echo "Inserting dyn_$name abc"
    arr_insert dyn_$name "abc"
    echo "Inserting dyn_$name def"
    arr_insert dyn_$name "def"
    echo "Inserting dyn_$name ghi"
    arr_insert dyn_$name "ghi"
    echo "Inserting dyn_$name $name"
    arr_insert dyn_$name "$name"
done

for name in "${array_names[@]}" ; do
    echo "Setting dyn_$name[0]=first"
    arr_set dyn_$name 0 "first"
    echo "Setting dyn_$name[2]=third"
    arr_set dyn_$name 2 "third"
done

declare -a | grep "a dyn_"

for name in "${array_names[@]}" ; do
   arr_got=($(arr_get dyn_$name))
   declare -p arr_got
done


for name in "${array_names[@]}" ; do
    echo "Dumping dyn_$name by index"
    # Print by index
    for (( i=0 ; i < $(arr_count dyn_$name) ; i++ )) ; do
        echo "dyn_$name[$i]: $(arr_at dyn_$name $i)"

    done
done

for name in "${array_names[@]}" ; do
    echo "Removing elements in dyn_$name"
    eval declare -p dyn_$name
    # arr_delete dyn_$name '^fir'
    # arr_delete dyn_$name 'i'
    # arr_delete dyn_$name 'ird'
    arr_delete dyn_$name '^de'
    eval declare -p dyn_$name
done


declare -a cmplxArr='([0]="preffoo" [1]="bar" [2]="foo" [3]="prefbaz" [4]="baz" [5]="prefbar" [6]="pref with spaces" [7]="pref
with
new line" [8]="
pref with new line before")'

arr_delete cmplxArr 'foo'
declare -p cmplxArr