$ curl -L -v -F "value=@myfile" "http://domain.tld/whatever.php"
Feb. 15, 2012, 11:26 p.m.
—
openiduser14
Explanation
curl read "man curl" if you need to info like using cookies,etc. you can also use wget-L follow redirects-v be verbose-F an input field value= the name of the input field @myfile the file you want uploaded"http://domain.tld/whatever.php" the url that will take the file