Hi, Thank you Viktor, that is absolutely perfect!
In particular, your explanation -- "The file content is interpolated into the value of the parameter, as though each line were an indented continuation of the parameter..." -- clarifies exactly what I needed to know. I am sure it's not in the documentation anywhere. It's not clear where would be a good place to write it up, without repeating the explanation in-line everywhere a file argument is mentioned. The additional clarification about comments needing to start in the first column was helpful, and good to know about the additional points regarding !negation and files including files etc. Thanks again! James. On Tue, 12 Jan 2021 at 01:22, Viktor Dukhovni <postfix-us...@dukhovni.org> wrote: > > On Tue, Jan 12, 2021 at 01:00:26AM +0000, JL (Postfix Readers A/c) wrote: > > > Can someone point me at the right place in the docs, or offer advice > > which maybe could also be added to the docs (!) to help others? > > Each main.cf parameter documents its syntax. Â Various parameters, that > take literal lists of values in-line, also take a file name whose > content contains similar values. Â The syntax typically also supports > "!/some/path", which is a set of exceptions. > > > Can such a file contain comments, for example? Or blank lines? > > Can it have several "items" space/comma separated on one line? > > Can it have each "item" on a line of its own? A mixture of both? > > Â Â http://www.postfix.org/postconf.5.html#relay_domains > > Â Â Specify a list of host or domain names, "/file/name" patterns or > Â Â "type:table" lookup tables, separated by commas and/or whitespace. > Â Â Continue long lines by starting the next line with whitespace. A > Â Â "/file/name" pattern is replaced by its contents; a "type:table" > Â Â lookup table is matched when a (parent) domain appears as lookup > Â Â key. Specify "!pattern" to exclude a domain from the list. The form > Â Â "!/file/name" is supported only in Postfix version 2.4 and later. > > The file content is interpolated into the value of the parameter, > as though each line were an indented continuation of the parameter > value: > > Â Â Â Â relay_domains = /some/file > > is the same as: > > Â Â Â Â relay_domains = > Â Â Â Â Â Â line1 > Â Â Â Â Â Â line2 > Â Â Â Â Â Â ... > Â Â Â Â Â Â lineN > > where line1, line2, ... lineN are the lines of the file. Â Comments must > start in the first column of the file. Â Blank lines are ignored, just > as they are in the in-line form. Â Files can even list more files, and > each '!' reverses the meaning of any previous '!'. > > These are called "match lists" internally, and it would perhaps be good > to have a general description of match lists somewhere... > > -- > Â Â Viktor.
