December 2002
Intermediate to advanced
1232 pages
56h 38m
English
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Name
$&
Synopsis
Normally, sendmail macros are expanded (replaced
with their values) when the configuration file is read. For those
situations when a sendmail macro should not be
expanded, but rather should be used in rules as is, V8
sendmail offers the $&
prefix. For example, consider the following RHS of a rule:
R... $w.$&M
Normally, when sendmail encounters this RHS in
the configuration file, it will recursively expand
$w into its final text value (where that text
value is your hostname, such as wash.dc.gov).
But because the M sendmail
macro is prefixed (here, with $&) it is not
expanded until the rule is processed.
The $& operator can be used in either the LHS
or RHS of a rule. The $& operator is described
in full in Section 21.5.3.
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.