PIPEFILE(1) PIPEFILE(1)
NAME
pipefile - attach filter to file in name space
SYNOPSIS
pipefile [ -d ] [ -r command ] [ -w command ] file
DESCRIPTION
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 direc-
tion.
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.
EXAMPLES
Simulate an old terminal:
% pipefile -w 'tr a-z A-Z' /dev/cons
% rc -i </dev/cons >/dev/cons >[2=1]
% echo hello
HELLO
%
Really simulate an old terminal:
% pipefile -r 'tr A-Z a-z' -w 'tr a-z A-Z' /dev/cons
% rc -i </dev/cons >/dev/cons >[2=1]
% DATE
THU OCT 12 10:13:45 EDT 2000
%
SOURCE
/sys/src/cmd/pipefile.c
SEE ALSO
mouse(8)
BUGS
Page 1 Plan 9 (printed 12/30/24)
PIPEFILE(1) PIPEFILE(1)
The I/O model of pipefile is peculiar; it doesn't work well
on plain files. It is really intended for use with continu-
ous 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.
Page 2 Plan 9 (printed 12/30/24)