s3tools/s3cmd — pull request #84 by bladealslayer (2012-10-11 10:36:36+00:00)
Title: Support condition headers in cp command

It is useful for the cp command to support the extra headers, because conditions such as x-amz-copy-source-if-modified-since can be given.
PreconditionFailed errors need to be accounted for in responses, as these are normal when conditions are specified.

Example usage:

```s3cmd cp -r -v --add-header "x-amz-copy-source-if-modified-since:`date -u -d '1 hour ago' | cut -d\ -f 1-4,6`" s3://source-bucket/ s3://dest-bucket/```