Why does a zip file appear larger than the source file especially when it is text?

Posted by PeanutsMonkey on Super User See other posts from Super User or by PeanutsMonkey
Published on 2012-08-29T06:39:59Z Indexed on 2012/08/29 9:41 UTC
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compression

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zip

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7-zip

I have a text file that is 19 bytes in size and having compressed the file using zip and 7zip, it appears to be larger. I had a read of the question on Why is a 7zipped file larger than the raw file? as well as Why doesn't ZIP Compression compress anything? but considering the file is not already compressed I would have expected further compression. Attached is a screenshot.

enter image description here

EDIT0

I took the example further by creating a file that contained random data as follows dd if=/dev/urandom of=sample.log bs=1G count=1 and attempted to compress the file using both zip and 7zip however there were no compression gains. Why is that?

enter image description here

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