AWS S3 bucket names

aws_s3_bucket_names.sh

#!/usr/bin/env bash

# get a list of S3 bucket names
# -----------------------------
# aws returns the bucket creation date and name:
# 2022-02-22 22:22:22 bucket-name
# additional logic is required to produce an array of names.

# pure bash
# https://github.com/dylanaraps/pure-bash-bible/issues/113
# "read returns 1 when everything is read, which is convenient when used in a while loop"
# note that, in this case, `read -d "\n"` and `IFS=$'\n' read -d ""` may be different
BUCKETS="$(aws s3 ls)"
IFS=$'\n' read -d "" -ra BUCKETS_ARRAY <<<"$BUCKETS" || true
for i in "${!BUCKETS_ARRAY[@]}"; do
  BUCKETS_ARRAY[i]="${BUCKETS_ARRAY[i]##* }"
done
echo "Pure Bash: ${#BUCKETS_ARRAY[@]} buckets"

# pure bash 4+ using mapfile
# https://github.com/dylanaraps/pure-bash-bible/issues/38
if [[ "${BASH_VERSINFO[0]}" -lt 4 ]]; then
  echo "This example requires Bash 4+"
else
  BUCKETS="$(aws s3 ls)"
  mapfile -t BUCKETS_ARRAY <<<"$BUCKETS"
  for i in "${!BUCKETS_ARRAY[@]}"; do
    BUCKETS_ARRAY[i]="${BUCKETS_ARRAY[i]##* }"
  done
  echo "Pure Bash 4+ using mapfile: ${#BUCKETS_ARRAY[@]} buckets"
fi

# bash 4+ using mapfile with cut
if [[ "${BASH_VERSINFO[0]}" -lt 4 ]]; then
  echo "This example requires Bash 4+"
else
  BUCKETS="$(aws s3 ls | cut -d ' ' -f 3)"
  mapfile -t BUCKETS_ARRAY <<<"$BUCKETS"
  echo "Bash 4+ using mapfile with cut: ${#BUCKETS_ARRAY[@]} buckets"
fi