Hello team!

I have an cloud files containers where a lot of old files, not all of them have the name with timestamp, so i decided delete some by header value "Last-Modified" using swiftly.

As i read in swiftly documentation:
-h "If-Modified-Since" output results which Last-Modified valued greater than specified. 

I need vice versa behaviour to delete those object in my container who older than specified value. 

My guess it will look like:

swiftly for -h "If-Unmodified-Since: Mon, 01 Jan 2015 00:00:00 GMT" DbBackups do delete "<item>"

But, as you can see this command even not work as expected:
/usr/local/bin/swiftly for -h "If-Modified-Since: Thu, 07 Apr 2015 11:15:19 GMT" DbBackups do head '<item>'                                                                                                             1 ↵
Content-Length: 102512640
Content-Type:   application/x-tar
Etag:           734d3b48b906caae7fc7f4ca1b07a607
Last-Modified:  Sun, 05 Jan 2014 13:27:28 GMT
X-Timestamp:    1388928447.92308
X-Trans-Id:     tx3aae5b6191e849da90919-005989daf3dfw1

Content-Length: 207564800 Content-Type: application/x-tar Etag: 6455dfd1ca0fe48d9d7f77467c90ed89 Last-Modified: Sun, 05 Jan 2014 15:10:01 GMT X-Timestamp: 1388934600.32317 X-Trans-Id: tx702afa16054e43c3af11f-005989daf3dfw1
Content-Length: 10240 Content-Type: application/x-tar Etag: a861dfb2e30fcc00d3d4d5cc5d3f0ed7 Last-Modified: Sun, 05 Jan 2014 16:15:04 GMT X-Timestamp: 1388938503.12482 X-Trans-Id: tx82192839c6cf4f65acc4d-005989daf4dfw1