This will allow for combined commands (id;id):

cat passwd | parallel -S lo --pipe -q sudo -S bash -c id\;id

--onall and --pipe must still be combineable. Not sure how to do that best.

Currently we read a block and fork. Will it be OK if we read a block, copy the block to --onall, fork, and then read the next block? It will be sufficient for holding the password.

The problem would be if the command expects to get a copy of all the stdin (e.g. wc).

That seems reasonable, although it might still be useful to have a built-in option for running commands under sudo. It seems like this would be a common use case for system admins.

It would be nice if GNU parallel could handle executing remote ssh commands with sudo. This would require GNU parallel to ask the user for the sudo password at the terminal before running the jobs, then send the password to the sudo command's stdin using the sudo -S option. There could also be a --user option which tells sudo to execute the command as a user besides root, using the sudo -u <user> option.

SSH power tool has this functionality: http://code.google.com/p/sshpt/, but it's not as powerful as GNU parallel. This option would make it much easier to execute remote administrative commands over ssh.

Thanks!