#!/bin/bash

# Array

crew=(kermit piggy fozzie)  # set
crew[3]='sam eagle'         # set by index
echo "${crew[1]}"           # get by index
crew+=(gonzo 'dr pepper')   # append
echo ${#crew[@]}            # number of elements
for c in "${crew[@]}"; do   # all elements, like $@
  echo -n "$c, "
done; echo
# no prepend feature, but you can always do:
crew=(scooter "${crew[@]}")
for c in "${crew[@]}"; do echo -n "$c, "; done; echo


# Associative array aka key-value dictionary.

declare -A mark                    # mandatory
mark=([denise]=4 [bob]=9)          # set
mark[charles]=3                    # set one
mark+=([bob]=7 [alice]=5)          # set more
for k in "${!mark[@]}"; do         # all keys
  echo "$k has ${mark[$k]} marks"  # lookup
done