3 pipefile \- attach filter to file in name space
20 to attach a pair of pipes to
25 between the true file and the simulated file that subsequently
26 appears in the name space.
29 interposes a filter that will affect the data delivered to programs that read from
32 interposes a filter that will affect the data written by programs to
40 process in the other direction.
44 has been run, the filters are established for programs that subsequently
47 programs already using the
54 twice, once for each direction. If the
56 is a single-use device, such as
60 flag to specify that the file is to be opened once, in
64 Simulate an old terminal:
67 % pipefile -w 'tr a-z A-Z' /dev/cons
68 % rc -i </dev/cons >/dev/cons >[2=1]
74 Really simulate an old terminal:
77 % pipefile -r 'tr A-Z a-z' -w 'tr a-z A-Z' /dev/cons
78 % rc -i </dev/cons >/dev/cons >[2=1]
80 THU OCT 12 10:13:45 EDT 2000
84 .B /sys/src/cmd/pipefile.c
90 is peculiar; it doesn't work well on plain files.
91 It is really intended for use with continuous devices such as
96 should be rewritten to be a user-level file system.
98 If the program using the file managed by
100 exits, the filter will see EOF and exit, and the file will be unusable
101 until the name space is repaired.