[chrismorgan]

For some reason I’m unsettled by the fact that, as presented, you have to unzip it once before it become a quine for subsequent unzippings. It lets you save 56 characters of base64 data, at the cost of `| gunzip`.

There’s some superfluous echo and subshell in there, incidentally; I like it better written this way:

  base64 -d <<<H4sIAAAAAAAAA5Pv5mCIeLzKnIGZgYHh/38GEYbX/+WxiDl1KB5hIIJ1TXfrBNeU3DznNGYG78SS1AKgEchsAEthdGVwAAAA | gunzip > quine.gz
  zcat quine.gz | diff - quine.gz