sendmail, 4th Edition

$@

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Specify a database-map argument

RHS database operator

When looking up information or performing actions with the $( and $) operators, it is sometimes necessary to provide positional substitution arguments. To illustrate , consider an entry such as this in a hypothetical database source file:

 hostA   %0!%1@%2 

With such an entry in place, and having built the database, the following rule could be used to perform a lookup:

 R$- @ $-.uucp   $: $(uucp  $@  $@ mailhost $: ..uucp $) 

Here, if the workspace contains the address [e-mail] , the LHS matches, causing it to be rewritten as hostA!joe@mailhost .

See Section 23.4.2 for a full description of how $@ is used in this way.