The seek0 program()

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 (https://cr.yp.to/qmail/) files that do multiple deliveries. For example:

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