pipefile – attach filter to file in name space|
pipefile [ –d ] [ –r command ] [ –w command ] file|
Pipefile uses bind(2) to attach a pair of pipes to file, using
them to interpose filter commands between the true file and the
simulated file that subsequently appears in the name space. Option
–r interposes a filter that will affect the data delivered to programs
that read from file; –w interposes a filter that will affect the
data written by programs to file. At least one command must be
specified; pipefile will insert a cat(1) process in the other
After pipefile has been run, the filters are established for programs that subsequently open the file; programs already using the file are unaffected.
Pipefile opens the file twice, once for each direction. If the
file is a single–use device, such as /dev/mouse, use the –d flag
to specify that the file is to be opened once, in ORDWR mode.
Simulate an old terminal:|
The I/O model of pipefile is peculiar; it doesn't work well on
plain files. It is really intended for use with continuous devices
such as /dev/cons and /dev/mouse. Pipefile should be rewritten
to be a user–level file system. |
If the program using the file managed by pipefile exits, the filter
will see EOF and exit, and the file will be unusable until the
name space is repaired.