List of files in a specific AWS S3 location in a shell script.

aws_s3_ls.sh

#!/bin/bash

# setup AWS CLI first
#  http://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-set-up.html

# configure AWS CLI (e.g. use IAM role for S3 access)
export AWS_DEFAULT_REGION=us-east-1
export AWS_ACCESS_KEY_ID=IDHERE
export AWS_SECRET_ACCESS_KEY=KeyHere

# s3 ls command
#  http://docs.aws.amazon.com/cli/latest/reference/s3/ls.html

# space-separated string (contains dates etc.)
flist=$(aws s3 ls s3://bucket.name/directory/path/)

# file list as an array
flist=(`aws s3 ls s3://bucket.name/directory/path/ | awk '{print $4}'`)
# first element
echo $flist
# NOTE: indexing starts with 0
echo ${flist[0]}
# all elements
#  http://stackoverflow.com/questions/15224535/bash-put-list-files-into-a-variable-and-but-size-of-array-is-1
echo ${flist[@]}

If you want to iterate over files, try the following:

flist=`aws s3 ls s3://bucket.name/directory/path/ | awk '{print $4}'`

for i in $flist
do
{
    # perform what you want for each file "$i"

    # for example to copy a file and tar it, you could do the following
    aws s3 cp s3://bucket.name/directory/path/"$i" /local/path/
    tar cvf /local/path/"${i%.*}".tar  /local/path/"$i"

    # copy back to new s3 bucket
    aws s3 cp /local/path/"${i%.*}".tar s3://bucket.name/directory/new_path/

    # remove local files
    rm /local/path/"$i"
    rm /local/path/"${i%.*}".tar
}
done