When wget and curl know better than you do: unwanted automatic decompression

[Joshua Root]

On 2015-1-21 20:19 , Mojca Miklavec wrote:
> Hi,
> 
> I have troubles testing the new version of CMake. Reason?
> 
> Here's what happens on a linux box:
> 
>> curl http://www.cmake.org/files/v3.1/cmake-3.1.0.tar.gz -o cmake-3.1.0.tar.gz
>   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
>                                  Dload  Upload   Total   Spent    Left  Speed
> 100 5816k  100 5816k    0     0   737k      0  0:00:07  0:00:07 --:--:--  791k
> 
>> file cmake-3.1.0.tar.gz
> cmake-3.1.0.tar.gz: gzip compressed data, last modified: Mon Dec 15
> 21:19:37 2014, from Unix
> 
>> md5sum cmake-3.1.0.tar.gz
> 188eb7dc9b1b82b363bc51c0d3f1d461  cmake-3.1.0.tar.gz
> 
>> gzip -d cmake-3.1.0.tar.gz
>> md5sum cmake-3.1.0.tar
> 6da9011024a215073c3b390e9ed6ee21  cmake-3.1.0.tar
> 
> 
> And here's what happens on my mac:
> 
>> curl http://www.cmake.org/files/v3.1/cmake-3.1.0.tar.gz -o cmake-3.1.0.tar.gz
>   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
>                                  Dload  Upload   Total   Spent    Left  Speed
> 100 29.8M  100 29.8M    0     0  22.5M      0  0:00:01  0:00:01 --:--:-- 22.5M
> 
>> file cmake-3.1.0.tar.gz
> cmake-3.1.0.tar.gz: POSIX tar archive
> 
>> md5 cmake-3.1.0.tar.gz
> MD5 (cmake-3.1.0.tar.gz) = 6da9011024a215073c3b390e9ed6ee21
> 
> Can anyone understand why both curl and wget happily automatically
> decompress the file on my Mac? This happens with both the original
> version in /usr and the version shipped by MacPorts.
> 
> 
> (At first I was questioning the weird behaviour of MacPorts that
> refused to extract the file, while "tar xvzf cmake-3.1.0.tar.gz"
> worked just fine. But it seems that "tar xvzf" simply ignored the fact
> that the file wasn't compressed.)

Adding the -i option to curl in both cases so it prints the headers may
be enlightening?

- Josh