102 lines
1.8 KiB
Plaintext
102 lines
1.8 KiB
Plaintext
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.TH PIPEFILE 1
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.SH NAME
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pipefile \- attach filter to file in name space
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.SH SYNOPSIS
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.B pipefile
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[
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.B -d
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] [
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.B -r
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.I command
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] [
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.B -w
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.I command
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]
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.I file
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.SH DESCRIPTION
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.I Pipefile
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uses
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.IR bind (2)
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to attach a pair of pipes to
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.IR file ,
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using them to
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interpose filter
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.I commands
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between the true file and the simulated file that subsequently
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appears in the name space.
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Option
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.B -r
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interposes a filter that will affect the data delivered to programs that read from
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.IR file ;
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.B -w
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interposes a filter that will affect the data written by programs to
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.IR file .
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At least one
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.I command
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must be specified;
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.I pipefile
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will insert a
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.IR cat (1)
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process in the other direction.
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.PP
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After
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.I pipefile
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has been run, the filters are established for programs that subsequently
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open the
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.IR file ;
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programs already using the
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.I file
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are unaffected.
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.PP
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.I Pipefile
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opens the
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.I file
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twice, once for each direction. If the
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.I file
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is a single-use device, such as
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.BR /dev/mouse ,
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use the
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.B -d
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flag to specify that the file is to be opened once, in
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.B ORDWR
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mode.
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.SH EXAMPLES
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Simulate an old terminal:
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.EX
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.IP
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% pipefile -w 'tr a-z A-Z' /dev/cons
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% rc -i </dev/cons >/dev/cons >[2=1]
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% echo hello
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HELLO
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%
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.EE
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.PP
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Really simulate an old terminal:
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.EX
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.IP
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% pipefile -r 'tr A-Z a-z' -w 'tr a-z A-Z' /dev/cons
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% rc -i </dev/cons >/dev/cons >[2=1]
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% DATE
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THU OCT 12 10:13:45 EDT 2000
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%
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.EE
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.SH SOURCE
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.B /sys/src/cmd/pipefile.c
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.SH SEE ALSO
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.IR mouse (8)
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.SH BUGS
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The I/O model of
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.I pipefile
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is peculiar; it doesn't work well on plain files.
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It is really intended for use with continuous devices such as
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.I /dev/cons
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and
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.IR /dev/mouse .
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.I Pipefile
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should be rewritten to be a user-level file system.
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.PP
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If the program using the file managed by
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.I pipefile
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exits, the filter will see EOF and exit, and the file will be unusable
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until the name space is repaired.
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