ref: 6c2f8fd5e4f0e0be44495a5526930fa3760cd87e
dir: /man/6/plumbing/
.TH PLUMBING 6 .SH NAME plumbing \- plumbing rules .SH DESCRIPTION Plumbing rules tell .IR plumber (8) how to route plumbing messages generated by applications using .IR plumbmsg (2). .PP 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 .B # and continue to end of line. Single quotes protect special characters (use .B '' to get a single quote). .PP A pattern has the general form: .IP .I "field verb arg" .PP Each .I field corresponds to a field in the incoming plumbing message: .RS .TP .B src Source application .TP .B dst Destination port .TP .B dir Working directory .TP .B kind Format of the data (eg, .B text or .BR image ) .TP .B attr A line of .IB name = value pairs .TP .B data The message data (an array of bytes) .RE .PP The verbs are: .RS .TF matches .PD .TP .B is Exact string comparison with .I arg .TP .B matches Regular expression comparison with .I arg .TP .B isdir .I Arg must name an existing directory .TP .B isfile .I Arg must name an existing file .TP .B set Set the value of the .I field to .IR arg . This verb operates in place, so put it after all other patterns in the rule. .RE .PP The .I arg can refer to one of the following variables: .RS .TF "$0 to $9 " .PD .TP .BR $0 " to " $9 Substrings resulting from the most recent regular expression match: .B $0 is the entire substring; .B $1 the first parenthesised substring, etc. .TP .B $file The file name examined by the last .B isfile verb. .TP .B $dir The directory name examined by the last .B isdir verb. .RE .PP The following actions are provided: .RS .TP .BI "plumb to" " port" Route the message to the given plumbing .IR port . .TP .BI "plumb start" " command arg ..." If no program is currently listening on the current rule's .IR port , start the .I command with the given arguments. The .RB ` $ ' 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. .RE .PP For example, the following rule sends the names of module files\- file names ending with suffix .RB ` .m '\- to .IR wm-brutus (1), starting it if it is not already running: .IP .EX 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 .EE .PP Note the use of .B $2 in the .B start action to pass .B brutus the line number selected by the second parenthesised expression in the pattern. .SH FILES .BI /usr/ user /lib/plumbing .SH SEE ALSO .IR plumb (1), .IR plumbmsg (2), .IR plumber (8)