Download unpublished Google spreadsheet as CSV

Maybe I'm not correctly understanding what you're trying to do, but I found a solution in this article that works just fine for me.

In the article, the author creates a download link for the spreadsheet as an XLS file (using "&output=xls”), but I tried "&output=csv" and successfully downloaded a correct CSV file.

Here's the download link to my "Download Test Spreadsheet", constructed just the way the author of the article suggested, but with "csv" substituted for "xls":

https://docs.google.com/spreadsheet/ccc?key=0At2sqNEgxTf3dEt5SXBTemZZM1gzQy1vLVFNRnludHc&output=csv

The link is anonymous (i.e., "Anyone who has the link can view"), and I downloaded it without logging into my Google account. I'll admit that I didn't use wget to do it (I just used a browser -- I didn't have wget installed), but I can't think of a reason that wget wouldn't work just as well.

Actually, I just grabbed a copy of wget and tried it, and it downloads the file correctly too:

% wget --no-check-certificate --output-document=test.csv 'https://docs.google.com/spreadsheet/ccc?key=0At2sqNEgxTf3dEt5SXBTemZZM1gzQy1vLVFNRnludHc&output=csv'

< bla bla bla, reams of output from wget >

% cat test.csv
Foo,Bar,Baz
1,2,3
4,5,6

So there ya go...

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UPDATING FOR 2018

As commented by @AndyMortimer, the new download URL is
  https://docs.google.com/spreadsheets/d/<KEY>/export?gid=<GID>&format=csv
where <KEY> and <GID> can be obtained from your navigation's URL,
  https://docs.google.com/spreadsheets/d/<KEY>/edit#gid=<GID>

PS: spreadsheets may have multiple workbooks, GID is the desired workbook ID. One-workbook-spreadsheet usually has gid=0, but if you add more they'll have random numbers (the GID is preseved even changing tab-order).

So, using wget and the same spreadsheet,

   wget --no-check-certificate -O test.csv \
    'https://docs.google.com/spreadsheets/d/0At2sqNEgxTf3dEt5SXBTemZZM1gzQy1vLVFNRnludHc/export?gid=0&format=csv'

I'm able to get a wget-able URL from public spreadsheet URLs that look like this:

https://docs.google.com/spreadsheets/d/LONG_ID_STRING/edit?usp=sharing

by changing them to look like this:

https://docs.google.com/spreadsheets/d/LONG_ID_STRING/export?format=csv

so that my wget command would look like:

$ wget "https://docs.google.com/spreadsheets/d/LONG_ID_STRING/export?format=csv"

Make sure you share the spreadsheet first with the blue "Share" button in the top right, then "Get Sharable Link".