curl命令怎么用 curl常用命令及参数详解(9)

curl命令怎么用

Example, get a page that wants my name passed in a cookie:

curl -b "name=Daniel" www.sillypage.com

Curl also has the ability to use previously received cookies in following sessions. If you get cookies from a server and store them in a file in a manner similar to:

curl --dump-header headers www.example.com

... you can then in a second connect to that (or another) site, use the cookies from the 'headers' file like:

curl -b headers www.example.com

While saving headers to a file is a working way to store cookies, it is however error-prone and not the preferred way to do this. Instead, make curl save the incoming cookies using the well-known Netscape cookie format like this:

curl -c cookies.txt www.example.com

Note that by specifying -b you enable the "cookie awareness" and with -L you can make curl follow a location: (which often is used in combination with cookies). So that if a site sends cookies and a location, you can use a non-existing file to trigger the cookie awareness like:

curl -L -b empty.txt www.example.com

The file to read cookies from must be formatted using plain HTTP headers OR as Netscape's cookie file. Curl will determine what kind it is based on the file contents. In the above command, curl will parse the header and store the cookies received from www.example.com. curl will send to the server the stored cookies which match the request as it follows the location. The file "empty.txt" may be a nonexistent file.

To read and write cookies from a Netscape cookie file, you can set both -b and -c to use the same file:

curl -b cookies.txt -c cookies.txt www.example.com

Progress Meter
The progress meter exists to show a user that something actually is happening. The different fields in the output have the following meaning:

% Total    % Received % Xferd  Average Speed          Time             Curr.
                               Dload  Upload Total    Current  Left    Speed
0  151M    0 38608    0     0   9406      0  4:41:43  0:00:04  4:41:39  9287
From left-to-right:

% - percentage completed of the whole transfer
Total - total size of the whole expected transfer
% - percentage completed of the download
Received - currently downloaded amount of bytes
% - percentage completed of the upload
Xferd - currently uploaded amount of bytes
Average Speed Dload - the average transfer speed of the download
Average Speed Upload - the average transfer speed of the upload
Time Total - expected time to complete the operation
Time Current - time passed since the invoke
Time Left - expected time left to completion
Curr.Speed - the average transfer speed the last 5 seconds (the first 5 seconds of a transfer is based on less time of course.)