The open for writing on the pipe will block until someone opens the other end. This means that the command to be run will be run only when someone reads the pipe. This is designed to make the output of the pipe up to date.
The config_file is used to tell feedpipe the details of the feeds. Each line causes a process to be forked and a feed started. The lines are separated into the following space delimited fields:
Name of pipe
owner of pipe ("-" means uid of running process)
group of pipe ("-" means gid of running process)
mode to open pipe in
Command to feed to pipe
The command to send consists of all text starting at the second field.
The sequence backslash followed by a newline is ignored allowing large
lines to be split up for readability. Everything following the "#"
character is ignored as are blank lines after the above substitutions.
No further pre-processing is done on the line so any backslashes, other
than those preceding a newline, are passed to the command.