If you use the s3-bash utilities with Amazon’s S3 service, you’ll find that one of the parameters asks for a file that contains the secret key. There’s important thing to note about this file – it must contain just the secret key without a newline. To check this, listing the file with ls -l should show that the file is 40 bytes. If it’s 41, you’ve got a newline and it won’t work. If you don’t have a text editor handy that will do this for you, you can use the following command to output your secret key to a file without the newline:
echo SECRET_KEY_HERE|tr -d '\n' > secret-key-file