The seek0 program

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 .qmail files that do multiple deliveries. For example:

$ cat .qmail
$ cat script
tomaildir ./foo
seek0 0
tomaildir ./bar