seek0 [fd ...] [: command arg ...]
seek0 seeks to the beginning of each given file
descriptor. Then it execs the given
command, if any. A colon
separates the file descriptors from the command.
This is useful, for example, in scripts called from
files that do multiple deliveries. For example:
$ cat .qmail |./script $ cat script tomaildir ./foo seek0 0 tomaildir ./bar