AWS S3 cli - tag all objects within a directory

Calvin Duy Canh Tran 's answer might return error for filename with spaces, in the command below, I added an -I flag for xargs to replace the argument "targetobject" with standard input.

aws s3api list-objects --bucket mybucket --query 'Contents[].{Key:Key}' --prefix testfolder/  --output text | xargs -n 1 -I targetobject aws s3api put-object-tagging --bucket mybucket --tagging 'TagSet=[{Key=colour,Value=blue}]' --key targetobject

There is no concept of a directory in S3. Here is a crude way of achieving what you want. Other posters may have a better solution. The following solution first gets all the objects in the folder and then calls put-object-tagging for each one of them. Note: I didn't test this solution.

aws s3api list-objects --bucket mybucket --query 'Contents[].{Key:Key}' 
    --output text | grep foo/bar/ | xargs aws s3api put-object-tagging 
    --bucket mybucket --tagging 'TagSet=[{Key=colour,Value=blue}]' --key

helloV's answer is corrected (have tested it) but it's not a good solution if the bucket is big, aws will take time to scan the whole bucket. Here is my solution

aws s3api list-objects --bucket mybucket --query 'Contents[].{Key:Key}' --prefix foo/bar --output text | xargs -n 1 aws s3api put-object-tagging  --bucket mybucket --tagging 'TagSet=[{Key=colour,Value=blue}]' --key

The command has 2 parts:

1. List all the object in prefix of bucket and output to text
2. Use xargs -n 1 to loop each of the result and tag it.