Question

Is there a command-line tool that could tell me if Gzip is on? What I’m looking for is something that can say the stream coming from the server is really gzipped even if the header params say Gzip:1 (which it could be falsely placing in the headers).

I don’t see a switch in curl, or wget, or tcpdump, or anything, but maybe I’m just missing something, or perhaps there is something else that could provide me this bit of information? Any help would be appreciated.

Answer 1

This shows Content-Encoding: gzip indicating compressed data. The data was then in gzip format, otherwise there would have been an error.

$ curl --compressed -v http://zlib.net > /dev/null

* About to connect() to zlib.net port 80 (#0)
*   Trying 69.73.181.135... connected
* Connected to zlib.net (69.73.181.135) port 80 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.19.7 (universal-apple-darwin10.0) libcurl/7.19.7 OpenSSL/0.9.8r zlib/1.2.3
> Host: zlib.net
> Accept: */*
> Accept-Encoding: deflate, gzip
> 
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0< HTTP/1.1 200 OK
< Date: Tue, 20 Mar 2012 23:19:00 GMT
< Server: Apache/2.2.21 (Unix) mod_ssl/2.2.21 OpenSSL/0.9.7a mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635
< Last-Modified: Mon, 06 Feb 2012 03:46:25 GMT
< ETag: "29603b0-84b4-4b84381b0a640"
< Accept-Ranges: bytes
< Vary: Accept-Encoding,User-Agent
< Content-Encoding: gzip
< Content-Length: 9508
< Content-Type: text/html
< 
{ [data not shown]
100  9508  100  9508    0     0  24955      0 --:--:-- --:--:-- --:--:-- 50574* Connection #0 to host zlib.net left intact

* Closing connection #0