devd.conf(5): explain internal vs. shell variables

[joerg]

Summary

devd.conf by default considers many variables as internal, possibly expanding them to an empty string.
shell variables thus need to be wrapped into braces.

Test Plan

Eyeball review needed.

[mail_fbsd2.e4m.org]

Fine with me, but please check my comments.

sbin/devd/devd.conf.5

700

Should we write "Any text immediately following that..."?

And can a var really start with a minus sign? If yes, and there are just no vars starting with '-' at the moment, please ignore this comment.

[joerg]

Updated to reflect Andre's comments.

[joerg]

sbin/devd/devd.conf.5

700

OK

The asterisk and the minus sign form special variables. This is explained at the beginning of the "Variables" subsection.

[mail_fbsd2.e4m.org]

The asterisk and the minus sign form special variables.

That's what I thought as well. But what's mentioned in the manpage are asterisk and underscore ;-).

[joerg]

In D48154#1098320, @mail_fbsd2.e4m.org wrote:

The asterisk and the minus sign form special variables.

That's what I thought as well. But what's mentioned in the manpage are asterisk and underscore ;-).

I correct myself: asterisk and underscore form special variables. However, minus signs are legal parts of any internal variable identifier, thus they are also allowed at the beginning of a name.

So in essence, $-foo, $_foo, and $*foo are all considered internal variables, undergoing normal variable replacement inside devd.
${mumble, $$$, $[ (to just name a few things) are all passed to the shell.