Just a little tip from a Git newbie using Windows and msysGit. Yesterday I couldn't push changes to my GitHub repository. I have no idea why... Maybe it had something to do with the size and number of files in the change set? Anyway, I kept getting error messages saying "unable to read from standard input" and "remote end hung up unexpectedly". After struggling with the problem for a while, I tried switching from PuTTY plink.exe to TortoiseSVN TortoisePlink.exe as the SSH client (export GIT_SSH="C:\Program Files\TortoiseSVN\bin\TortoisePlink.exe"), and for some reason, everything started to work again.
If anyone know why this problem occured, and why it was solved by switching SSH client, please let me know.