Plumbing rules tell
plumber(8)
how to route plumbing messages
generated by applications using
plumbmsg(2).
The file is a set of rules separated by blank lines.
Each
rule
is a set of patterns followed by a set of actions.
The rules are interpreted in order.
The first rule whose patterns all match is applied, and no further
rules are examined.
Comments start with
#
and continue to end of line.
Single quotes protect special characters (use
''
to get a single quote).
A
pattern
has the general form:
-
- field verb arg
Each
field
corresponds to a field in the incoming plumbing message:
- src
- Source application
- dst
- Destination port
- dir
- Working directory
- kind
- Format of the data (eg,
text
or
image)
- attr
- A line of
name=value
pairs
- data
- The message data (an array of bytes)
The verbs are:
- is
- Exact string comparison with
arg
- matches
- Regular expression comparison with
arg
- isdir
- Arg
must name an existing directory
- isfile
- Arg
must name an existing file
- set
- Set the value of the
field
to
arg.
This verb operates in place, so put it after all other patterns in the rule.
The
arg
can refer to one of the following variables:
- $0 to $9
- Substrings resulting from the most recent regular expression match:
$0
is the entire substring;
$1
the first parenthesised substring, etc.
- $file
- The file name examined by the last
isfile
verb.
- $dir
- The directory name examined by the last
isdir
verb.
The following actions are provided:
- plumb to port
- Route the message to the given plumbing
port.
- plumb start command arg ...
- If no program is currently listening on the current rule's
port,
start the
command
with the given arguments.
The
`$'
variables listed above can be used, to include part
of the message in the command line arguments to the program.
They are replaced in the command string by their actual values.
For example, the following rule sends the names of module files-
file names ending with suffix
`.m'-
to
wm-brutus(1),
starting it if it is not already running:
-
kind is text
data matches '([a-zA-Z0-9]+.m)(:[0-9]+)?'
data isfile /module/$1
data set /module/$0
plumb to edit
plumb start /dis/wm/brutus.dis $file$2
Note the use of
$2
in the
start
action to pass
brutus
the line number selected by the second parenthesised
expression in the pattern.