Beginner Question: Best way to substitute variables

[Florent Thoumie]

Frank Behrens a écrit :

> Meanwhile I use FreeBSD for several years and now comes the time to 
> give something back. I'm creating a port and could not find an answer 
> to my question:
> 
> What is the best way to set variables in scripts (e.g. pkg-install) 
> and text files (e.g. pkg-message) depending from Makefile variables 
> (e.g. PREFIX)? 
> I understand the Makefile rules and it is no problem to use variable 
> paths depending from $PREFIX, $DOCSDIR and other, but how they are 
> later used in scripts, like pkg-install and rc.d/scripts? IMHO 
> changing these and other variables in the Makefile should be enough 
> to adjust the complete port.
> 
> As a possible solution I see:
> Put all files in a separate directory, create Makefile dependencies 
> and replace the desired strings with "sed". But this seems to be not 
> the usual way, I could not find any example port.
> 
> Please, could you point me to an example port, where this problem has 
> been solved in a practical way conform to FreeBSd development rules.

	The question is some weeks old now but I think I can add some
	piece of answer to the thread.

	Recently, 2 new variables appeared in bsd.port.mk that handles
	this kind of situation for you. See SUB_FILES and SUB_LIST in
	Mk/bsd.port.mk and net/bnbt or net/ldapsh for examples.

	Basically, you put file.in in ${FILESDIR} and set SUB_FILES=file.
	Substitution works like with pkg-plist, you can use %%VAR%% and
	it'll be replaced automagically. Some variables are added by default
	to SUB_LIST but you can add some (eg. SUB_LIST= RC_SUBR=$RC_SUBR).

	I began to wrote some documentation to add to the PH but I accidentally
	lost it. I'll try to do this ASAP.

	Best Regards.

-- 
Florent Thoumie
flz at xbsd.org